My grandfather had dementia, for a long time it was pretty hard to tell what was dementia and what was just him not giving a fuck. He was always someone who just did whatever he wanted and wasn’t afraid to go against the grain and didn’t really care what anyone thought of him, and he was kind of always that way. It would be really hard to pick apart which of his quirks were dementia related and what was just him. Standing naked in the doorway of his room at the nursing home waggling his dick at the lady across the hall sure sounds a lot like a dementia patient, but it also sounds like something an immature, womanizing troublemaker would do if they knew they were pretty much immune from getting in any actual trouble.
He didn’t have the most severe case of dementia, it didn’t progress super fast, I’m sure if I went months or years without seeing him I could have picked out some changes, but since we saw him regularly it was really difficult to see the changes over time.
And if he had an army of lackeys getting paid to cover up his mistakes and trying to keep him in line, he probably could have passed as relatively mentally competent almost up until the very end.
I won’t pretend that my grandfather’s moral compass always pointed north, but he definitely had one. He could also be pretty charming and personable when he wanted to. If he threw his morals out the window and had any political ambitions, he probably could have become an even more dangerous trump if someone had given him a small loan of a million dollars. Luckily all he ever really wanted to do was drive a bus.
Funnily enough, most of his siblings ended up fairly rich thanks to a successful business venture my grandfather wasn’t interested in. Those branches of the family turned out a lot of real conservative assholes, and once the money started drying up, also a lot of criminals a generation or two down the line.