Father’s Day found me with a man who often doesn’t remember who I am, although we have spent much of his 93 years together. My father has dementia.

Five years ago, I persuaded my parents to move from Spearfish, S.D., into a second house that my wife and I own that doubles as my office. Leaving a community where they were well-established was difficult. But they enjoyed seeing grandchildren, spent Saturdays at garage sales and played Upwords with me at lunch time. It was good.

I first noticed little things. Forgetfulness, confusing names. It’s part of aging, I thought.

A year ago, my parents’ world narrowed. A retired minister, my father began hurrying from church, afraid he might say something foolish. No more garage sales, no more word games. In October, my mom felt severe back pain. Cancer. My father slept next to the hospital bed that hospice delivered. They celebrated their 70th wedding anniversary in November. Three weeks later, she died. I learned then that she had been covering for him. At her funeral, he asked if I was enjoying “the party” and said he was sorry that my mother had missed it.