I did retirement home training and used to think it was a sweet job. Then I got in the business and underestimated how demoralizing it was as they give you the easy elders in training while the others make you, or at least me, really think of the fact the job just amounts to an unkarmic freebie.
Dementia often causes personality changes. It can make really nice people into assholes, and it can turn people who were real bastards into the reverse.