We went for a walk around my neighborhood and got lost.

I was three, and that’s what I remember as my earliest and most vivid memory of my paternal grandfather. Someone found us eventually, of course, and I was too young to really piece together that it was odd that a grown-up who’d visited my house for years would get both of us lost on a simple Sunday afternoon stroll. He was in his late fifties.

I was about five when the phone calls from my grandmother started coming with increased urgency: My grandfather had wandered out the front door again. He stepped onto a bus and wound up in the next city. A neighbor found him disoriented, standing near the corner shop. Sometimes, the searches went into the night, and she’d return in the dark, hugging and kissing him, fighting back tears. If she turned her back for a second—to take a quick shower, to cook dinner, to answer the phone—he could slip away.

He was a proud Marine who spent four years fighting in the Pacific during WWII; when he was lucid, he was just as proud and determined as he’d always been.

Soon after, I heard the word “Alzheimer’s” peppered in my parents’ conversations more and more. I didn’t know what it meant, but I knew each time I saw my grandfather, he talked less and less. Smiled less and less. Interacted less and less. I wasn’t scared of him exactly, but I was confused. I didn’t know how to reach him anymore.

No one did.

When his needs became too great and the amount of care he needed was more than any one human–however loving and devoted–could provide, he went into a nursing home. He was fairly young at the time, not much older than my own father is now, and his life was slowing reversing itself. He sat motionless in bed and our regular visits bore witness to each new loss: he no longer spoke. He no longer had the spark of recognition in his eyes he used to have even when words failed him. He no longer had the ability to control his bowels, or eventually, to feed himself.

My grandmother took the bus to visit him every day. My father took us often; what I remember most are his tears as he stroked the forehead of the man who no longer recognized his oldest son.

My grandfather died when I was a freshman in high school. He was buried on my fifteenth birthday, the same morning the bomb exploded in Oklahoma City. He was buried in Marine tradition; dress blues and taps and a gun salute accompanied his casket.

He died in 1995, but we lost him long before that. My father had grieved each loss for so many years that he said he’d already said goodbye to his father a hundred times over. I cried during the funeral, but I wasn’t crying for the man I would miss—Alzheimer’s had taken away any real relationship I could have had. I cried for all the things he’d missed and would cotinue to miss, the memories robbed: the high school graduations, the college ceremonies, the weddings and baptisms. Education was the most important thing to him—he stood over my father’s shoulder each night, making sure he didn’t take his Boston Latin school education for granted—and with each academic milestone we passed, my father would well up and say, “Your grandfather would have been so proud. He lived for this.”

Last week, Newsweek highlighted the challenges of caring for Alzheimer’s patients and predicted how huge an issue the disease would become in the next several decades. It brought back a flood of memories for me and an appreciation of what my grandmother and her children went through caring for my grandfather I couldn’t have had as a child or even a teenager.

I am so used to the physical aspects of giving and receiving care for chronic conditions—getting ice for someone, doing errands, asking for help carrying things. I have seen the way the body can be ravaged by disease and because I am used to it, I do not fear it too much.

But I cannot think of anything more terrifying than losing your memories, of words and names and faces slipping away day by day, of spiraling into a black hole of confusion so profound that by the time the body’s functions begin to systematically break apart, the mind isn’t even aware. Towards the end, the pain is even greater for the living, I think, for people like my grandmother who can only hold a cold, clenched hand in their own and remember what it was like to feel love from their own beloved.

For Father’s Day, my husband and I scanned three hundred pictures and created a DVD of them for my father. It meant so much to him, but we all benefited. I watched the photos from the early years flash across the screen—my grandfather holding me above a birthday cake, my grandfather in the middle of all of us cousins on Christmas, my grandparents with their arms around each other, smiling. You could see his gaze grow more vacant through the years, but he was there.

“Pictures are such great sources of memories because you never take them when you are angry or sad, they are usually so happy,” my mother said. She was right, but I loved these pictures the most because through them, I saw that he did know me once. He did hug me and hold me and say my name. We did have a relationship, if briefly.

And for however sick my father is, I am unspeakably grateful that at the same age his own father started growing blank and withdrawn, his mind is strong, clear, and sharp. He will continue to make memories—and keep them.