My 76-Year-Old Mother Begged Me Not to Leave Her Alone With My 28-Year-Old Son. Every Night, He Locked Her Bedroom Door, and Every Morning, She Looked More Terrified. But When I Installed a Hidden Camera and Saw What He Was Carrying Into Her Room at 3 A.M., I Called the Police…

Daniel handed it to me.

Inside was a letter written in my mother’s familiar handwriting, dated several weeks earlier.

My dear Daniel,

Please don’t tell Margaret until I’m ready. I know something is happening to my memory. Yesterday, I forgot my own daughter’s birthday. I saw the hurt in her eyes, and I couldn’t bear it.

I’m afraid she’ll stop seeing me as her mother and start seeing me as someone who needs to be taken care of.

Please help me understand what’s happening before we tell her.

Love, Grandma.

I read the letter three times.

Then I remembered something.

Two months earlier, my mother had forgotten my birthday.

I had been angry.

I’d told her, “Mom, you’re getting careless. You used to remember everything.”

She had apologized repeatedly.

I hadn’t realized how frightened she already was.

“Why was she screaming tonight?” I asked Daniel.