My younger brother, Michael, takes offense when I remark that our once socially adept, ninety-two-year-old mother has all the conversational skills of a windup doll. I’m referring to the supply of one-size-fits-all phrases she uses to hide her dementia: “Fortune favors the brave,” “It’s a great life if you don’t weaken,” and “Every silver lining has its cloud” are her three favorites. Talking with Mother is like trying to converse with a handful of fortune cookies, I tell Michael.

“Jesus,” he hisses. “That’s so typical. Do you have any idea how cruel that sounds?”

Yes, I do, now that he mentions it. But aging is cruel. Life is cruel. Is that my fault? It’s not as if I said it to her face. Still, I regret the remark, if only because it gives Michael a chance to grab the moral high ground. He thinks I’m a cynical know-it-all. I think he’s a self-righteous jerk. But the real basis of our enmity is that we are, in certain important ways, alike — something for which we can’t quite forgive each other.

We both struggle to play the role of devoted son. I can’t spend two minutes with our mother without becoming exhausted. “Mother,” I’ll say as pleasantly as I can after bringing her a glass of water, “please drink this. It must be ninety degrees in here. You’ll get dehydrated and end up in the hospital again.”

We Craigs are a formal people. My parents have been “Mother” and “Father” for as long as I can remember, while we three brothers have always been Benjamin (the eldest, who lives in another state and has little contact with us), Alan, and Michael. No one in the family would use “Ben” or “Al” or “Mike” any more than we would “darling” or “sweetheart.”

“Dr. Fleckle over here,” snorts my mother, ignoring the proffered water. This is her standard insult whenever I suggest something having to do with her health. I catch my reflection in her bureau mirror: I look as if I’ve just swallowed some bad peanuts.

“Fine, Mother,” I say. “Do what you want. So I’ll spend another eight hours in the emergency room with you after you faint in the hallway again. It’s not like I have better things to do.”

My mother’s contempt for me would be easier to take if I didn’t share it. I hear the aggrieved sanctimony in my voice just as clearly as she does. It’s always painful to realize how much like Michael I sound.

My wife, Anne, can’t understand why I’m not more patient. “I know you and your mother have always had your issues,” she says, “but you have to remember, she’s no longer the same woman.”

But that’s where she’s wrong. In spite of my mother’s deepening dementia, she is still unmistakably herself. What’s gone are many of her good qualities: her quick wit; her passion for politics and liberal causes; her love of animals, music, and books; her considerable charm, which she was always able to call on, no matter how stressful the circumstances. When my father was confined to intensive care after a heart attack, she had the nurses and doctors treating them both like celebrities.

It’s not that she can’t still be sweet at times, especially when approached with kindness; in fact, there are occasions when I think my mother’s disposition has actually mellowed. But then she’ll say something hypercritical that reminds me of the qualities that have always made her hard to take. My mother has rarely been able to abide any form of human weakness. In her eyes, even aging and illness are evidence of moral laxity. Not long ago I gently broke the news that her ninety-four-year-old brother had shattered his hip and might not survive. “Oh, isn’t that just like him,” she replied. In fairness, she probably wasn’t able to grasp what I was telling her, but her response was still pure Mother.

“Tincture of Mother,” I said recently to Michael with a wink, after a particularly trying visit. “Do not exceed recommended dosage.”

My brother is nothing if not predictable. (I’m sure he’d say the same about me.) He sprang to Mother’s defense, reminding me that she doesn’t know what she’s saying — and, anyway, do I think I’m so easy to be around?

On the contrary. Like everyone else in the family, I can’t stand myself at least half the time. I crack bad jokes because, if I didn’t, I’m not sure I could cope. Besides, I can’t help thinking I have the right to make jokes. It’s Anne and I who do most of the work of caring for Mother. We pay her bills, get her to her doctor appointments, do her shopping, and deal with the staff at the Green Hills Retirement Community. I’m all too painfully aware that I don’t do these things out of love — or, at least, not anything that feels like love — but rather out of a grim sense of responsibility that I struggle not to resent.

The truth is I’ve always resented my mother. When I was growing up, her prodigious rants, often delivered while making supper for my brothers and me, were masterpieces of performance art. She rose to near-biblical heights of suffering and self-pity.

“Dear God,” she would call out as she dished pepper steak from the frying pan onto our plates, “what terrible thing have I done to deserve such children?” My brothers and I would sit at the kitchen table with our heads bowed, waiting for the storm to pass. “Do you hear me?” she would ask us while she served our food, as if there were some doubt about whether our ears worked. “I’m asking God what I did to deserve such . . . such . . . I don’t even know what to call you anymore.” Pouring each of us a glass of milk, she’d continue her conversation with the Almighty. “Can you tell me what they are, God? Because the very last thing they are is children.” I always had the sense that God was just as vexed as my mother concerning what we might be.

I kept hoping our father — a kind, preoccupied, impatient, uncomfortable man — would step in and defend us, but he never did. I don’t remember holding it against him much. In the Craig family it was every man for himself. He had to live with our mother just as we did.

Even as my mother progressed through her eighties, it didn’t occur to me that she might get dementia. None of our often-long-lived relatives has had it. She celebrated her eighty-third birthday by going for a two-mile jog. At eighty-six she was still playing bridge and tackling the New York Times crossword puzzle. During the 2008 presidential primaries she was an enthusiastic Hillary Clinton supporter and would argue me, an Obama man, to a standstill.

I expected the physical depredations of old age. What I’m struck by is how vacant my mother has become, how lost. Unable to read, follow a television program, or take meaningful part in a conversation, she clings to endless games of solitaire. Since she’s forgotten the rules, this consists of nothing more than arranging the cards into random piles. Of course she “wins” every time, looking up at me with a sly smile as she gathers up the cards. That I feel the urge to point out she’s not playing properly fills me with self-loathing.

It was shortly after my mother broke her hip that she began to show signs of cognitive decline. Or maybe it was just before that. My father died in the autumn of 2008, and she insisted on going down as usual to their Florida condo for the winter. I was pretty sure the trip would end badly. She still seemed understandably grief-stricken and, in hindsight, a bit bewildered. Even more worrisome, she was mixing alcohol with the tranquilizers her doctor had prescribed. A week or so before she was to leave, I found her lying sodden and mumbling on her living-room floor, too intoxicated to stand.

Our family has a history of addiction. Car wrecks and court dates were common occurrences for my brothers and me all through our late teens and early twenties. It was a rare couple of months when one of us didn’t get into some sort of trouble related to drinking. We lived in a state of perpetual disgrace.

My father, at least, was a friendly drunk. Alcohol softened him, made him almost tender. He’d stumble into the house smiling sheepishly, the front of his pants stained dark with urine. Calling us “my good boys,” he’d hand out five-dollar bills all around, as if paying a self-imposed fine. Our father never seemed happier than when he was drunk enough to give us little gifts.

Although I always drank more than my share of alcohol, as I got older I came to prefer drugs, especially narcotics, which to my mind had a certain hip sophistication. I read Naked Lunch in college and fancied I would be the next William S. Burroughs. I even tried to write like him.

But it was Xanax, a lowly tranquilizer Burroughs wouldn’t have been caught dead taking, that proved to be my undoing. An overdose resulted in a week in the hospital, a long stint in rehab, and a hellish year of debilitating withdrawal symptoms. Even as I slowly recovered, I knew I was finished as an addict. The certainty that I couldn’t survive another such ordeal precluded the possibility of a relapse. I was thirty-six.

Until the day I found her on her living-room floor, I’d thought my mother was the exception to the family tendency toward addiction. I couldn’t recall ever seeing her impaired, despite her regular use of sleep aids and what she called “my headache pills.” She seemed too strong and too proud to lose control in such a demeaning way.

It turns out she was just late to the party, and when she finally did arrive, it was with her usual flair. A son hasn’t really lived until he’s had to remove his intoxicated mother’s clothes in order to get her into bed.

About a month after my mother arrived at the Florida condo, I got a call from her neighbor informing me that the building superintendent had found her on her bathroom floor, unable to move. She might have been lying there for as long as twenty-four hours. The admitting doctor at the hospital noted that she appeared “under the influence.” Whatever she’d been taking, it had been in sufficient quantity to still be in her system a day later.

Anne immediately flew down, nursed her mother-in-law back to health, and then brought her home. I was shocked at how diminished my mother appeared when I picked them up at the airport. She barely spoke during the long ride back to her apartment.

Over the next six months or so I began to realize that Mother wasn’t paying her bills on time or keeping track of the checks she wrote. She kept losing her purse, her keys, her address book. (I eventually found the address book in the hall closet, under some towels.) She also backed her car into the stone wall that borders the Green Hills parking lot.

Certain that Michael must have been noticing some of the same signs, I called him to discuss what we should do. Since my brother and I rarely agree on anything, I was expecting we’d have trouble deciding how to proceed, but it hadn’t crossed my mind that he wouldn’t even concede there was a problem.

Michael and I have been fighting since childhood, sometimes with genuine animosity but more often simply out of habit. If we’re not fighting, we’re awkward around each other. The entire family is like that. When my brothers and I were growing up, screaming at one another was the common mode of communication, even in trivial exchanges: “It’s 9 AM, you moron! Get yourself a watch!” Around the kitchen table, dismissive hand waving and contemptuous laughter were the default response to all earnest opinions. We’d indulge in shouting matches the way other families might sit down to play Monopoly or Scrabble — which is to say, as mildly amusing pastimes that no one took too seriously.

But the extended argument Michael and I had over our mother’s care was unparalleled in its bitterness. We began communicating only by e-mail, manning our laptops as if they were battle stations.

“You’re fucking blind!” I typed furiously, teeth clenched as I clicked SEND.

“And you’re a paranoid screwball!!!” he responded. It was the multiple exclamation marks that got to me more than anything else.

Michael is far from stupid. He chose Crime and Punishment for summer reading between ninth and tenth grade, an age at which I was still hiding Batman comic books under my bed. But, like me, he’s stubborn. He’s also resistant to acknowledging the world’s unpleasantness. Many years ago we were in business together, and he refused to believe that an employee was stealing from us, despite what to me was overwhelming evidence. I, on the other hand, expect people to be stealing and am pleasantly surprised when it turns out they’re not. I see our opposing styles as expressions of the same fundamental Craig pathology: an inability to tolerate pain. I assume the worst in order to avoid being hurt. Michael does the opposite for precisely the same reason.

My fighting with Michael and my worries about our mother, especially concerning her finances and continued driving, began to affect my health. I was increasingly exhausted, popping in and out of anxiety-filled sleep all night long like a bobbing cork. I began having headaches and a persistent dull ache in my stomach.

I finally saw a doctor, who diagnosed stress-induced gastritis and gave me several prescriptions. One was for a tranquilizer: a benzodiazepine similar to Xanax. Another was for a dozen Vicodin to treat my headaches, the severity of which I’d automatically exaggerated out of an old addict’s habit.

Of course I should have handed the prescriptions back along with a brief explanation, but instead I slipped them into my pocket. Though I no more planned on filling them than most people who carry a gun plan on shooting someone, merely having them on my person made me feel better. I’ll throw them out when I get home, I told myself. Instead I stuck them in a desk drawer.

Until I had Michael’s consent, there wasn’t much I could do about protecting our mother’s money. Her financial records, to the extent that they even existed, had become indecipherable, and she’d written checks to various charities for more than she could afford. I also found a large check marked “donation” made out to her retirement community. “Mother, they’re a for-profit company,” I said. “Would you donate money to the grocery store?”

When I mentioned all of this to Michael, he replied that he was sure the charities she gave to were worthy causes, and even if they weren’t, it was her money.

“Jesus, Michael!” I shouted. “Who the hell do you think is going to be paying her bills if she runs out of funds?”

Her driving was an even greater problem. I’d had many arguments with Mother about it, but despite my best efforts to remain calm, my tone would quickly become accusatory, as if her dementia were her fault. I’d become angry, and she’d become angry, and then there was no way she’d agree to anything — certainly not to give up her prized car keys.

Without consulting Michael, I called my mother’s geriatric physician to seek her advice about Mother’s driving. Dr. Siegal was happy to set up an appointment with my mother and me, but it was six weeks away, and I fretted about what might happen in the interim. Sure enough, just a few days later Mother smacked her car into a pole at the local shopping mall, denting the fender.

When the appointment finally came, Dr. Siegal gave my mother a short test and concluded that she had mild to moderate dementia. Mother didn’t know the year (she guessed 2008 instead of 2010), the month (she said May instead of July), or the season (“I’m not sure”). Interestingly she had no trouble spelling world backward — something I’d likely have difficulty with myself.

At the end of the exam, the doctor gently reminded my mother that we cared about her and were trying to help her. “You’re a lovely woman,” she said. “I know you want to do the right thing. Won’t you give your son your car keys?”

To my amazement my mother promptly reached into her purse and handed them over. With a few kind words Dr. Siegal had accomplished what I’d been unable to in months of badgering.

The next day I got an e-mail from Michael accusing me of violating our mother’s “civil rights” in the matter of her keys. I got so mad my vision dimmed. Later I learned that he was under the impression I’d stolen them — because that’s what Mother had told him — but at the time his accusation struck me as unforgivably misguided. In my fury I found myself thinking about those two unfilled prescriptions.

“Slip” is too generous a term for what happened next. One slips on an icy sidewalk. Nobody picks up drugs again by accident, especially after twenty-five years. Of course, I had plenty of “reasons”: the headaches, the stomach pains, the stress of having to deal with Michael and our mother, the burden of being “right” when everyone else was “wrong.” I was three-quarters convinced that taking pills was the only way to save myself from a downward spiral of increasing ill health — that, in fact, it would be self-destructive not to take the drugs.

I never bothered with the tranquilizer. I’d abused Xanax in such high doses for so long that my brain receptors for benzodiazepines were little more than smoking holes. But Vicodin was just the thing.

Later, after I’d run out of pills, I tried to tell myself it was no big deal: Vicodin wasn’t that strong a painkiller, and I’d used it for just a couple of weeks — as if anything short of getting addicted to heroin didn’t really count — but of course damage had been done. Sobriety is cumulative and self-perpetuating; a quarter century is a long time. I’d sold cheap: about half a Vicodin for every hard-won sober year. At least I was able to stop.

The irony is, for those few weeks I was popping pills again, I was arguably a better man. Full of the boundless goodwill of the pleasantly buzzed narcotics addict, I visited my mother almost every day instead of the usual twice a week. I sat with her, held her hand, and reminisced about the old days — all wildly out of character for me, though she seemed not to notice.

I also reached out to Michael with a long, conciliatory e-mail. Bathed in chemically induced feelings of compassion, I told him that I loved him despite our differences.

“What are you on, anyway?” he replied, probably not joking.

“Just trying to make peace,” I wrote back sheepishly, the last of the Vicodin already wearing off. Naturally, the next morning my anger was back, but I was stuck with the truce I’d initiated.

A few weeks later my doorbell rang. I peeked out the window to see my brother standing at the front door, looking as if on the verge of tears. I’d seen this expression on Michael only a couple of times before. Once was when our mother had spit on him after he’d gotten arrested for possession of marijuana while a freshman in college. Another occasion was the day I’d told him he couldn’t stay at my place after his wife had thrown him out of their house. It wasn’t that I was unsympathetic to his plight, I told him. It was that I’d been sober less than a year, and there was no way I could live with an active drunk, even for a short while. We Craigs seldom if ever ask each other for anything, and I’m sure Michael felt humiliated. To his addict’s twisted way of thinking, I was really saying that I was better than him. He didn’t speak to me for several years, and when he finally did, it was only after he’d sobered up as well.

Now, at the sight of my brother in this emotional state, my anger melted away, this time for real. As I opened the door, I was suddenly possessed by a wild impulse to embrace him. It was only the look of alarm in Michael’s eyes that stopped me. Were those really my arms that had just twitched ever so slightly in my brother’s direction?

“I’m sorry, Alan,” Michael said. “I made things harder than they needed to be.” He had called Dr. Siegal, who’d confirmed that our mother did indeed have dementia and had given up her car keys of her own free will.

I hate being apologized to, mostly because it obligates me to say something gracious in return. Naturally I messed it up.

“No worries,” I told him. “In fairness, I spend more time with her than you do.”

I meant only that, due to my more regular contact, I was in a better position to notice her symptoms, but of course Michael took it as a backhanded rebuke. To our mutual relief we quickly returned to fighting, though without the recent bitterness.