Would just add re suicide, I dare say we'd all like to think we'd take that way out of dementia, but the trouble is, by the time it's past the very early stages, even if we had a stash of pills hidden away, we'd very likely forget we'd got them, and even that we'd planned to do such a thing at all. Very often people can't remember that they've got dementia, for the simple reason that they can't remember that they can't remember anything.
Even when she could no longer even make herself a cup of tea, my mother still thought there was nothing wrong with her. And I still remember the moment when it dawned on me that it was dementia and not just old-age forgetfulness - as I'd been trying to tell myself, having gone through dementia already with FiL and dreading it all over again.
My mother had always been very clued up about finances, , so when she phoned First Direct about something, and could not remember, literally the instant she'd put the phone down, what theyhad said, that was when the ghastly penny dropped.
And she was still in the very early stages then.
As for a 'kinder' death, e.g.a heart attack at home, it would certainly have been far kinder for my poor mother, than the pitiful wreck she finally became - doubly incontinent, not knowing any of her family, unable to hold any sort of conversation, zero dignity.
IMO it's a fate far worse than death.