Unfortunately this happened with my uncle as he dealt with severe early onset dementia.
He took to pooping in the shower and "discovering" the results in the tub when he was done. Then he started trying to hide it in his pockets.
He no longer understood how to wash himself, eat a bowl of cereal, etc. Towards the end he told my mom he forgot how to swallow.
He died suddenly just last month at the age of 62. We don't know if it had anything to do with the swallowing issue or not. Waiting on autopsy results.
That horrible disease hit him like a ton of bricks.
My FIL says he is in pain below his waist. For 10 minutes he tells us what is wrong. We figure out he has to go. He forgot how and we had to tell him how to go.
i hope this is not a hint of what will happen this weekend.