Rate me late if it's been posted already, but people apparently think dementia patients equals drooling retards unable to say a word. While it can be so, it mostly applies to the latest stage of it, with in-between usually consisting of raging unreasonable cunts. Some are also just cheerful forgetful grannies, but they're fairly rare.
Dementia stems from different deceases, with some affecting motor functions first and others messing with your brain. Respecting elders is good and so on, but cases I've stumbled upon were insufferable due to them appearing kinda normal and then pissing in teacups to wash them, hoarding junk and cutting up clothes in a search for some juicy government spy bugs. Popular science likes to spread awareness about "taking care" and "being gentle", but kinda avoids mentioning all possible outcomes.