fun with alzheimers

That is the problem a demented person is not of sound mind to make that decision. You can’t and shouldn’t be able to do it for them. My mom and dad went thru it with my grandmother. And they always said they didn’t want to put me thru the hell that grandma put them. But they didn’t have enough of their wits to know that it was exactly what they did to me.
I don't know if a living will made way before they get bad would work. Is it legal in the U.S.?