I don't understand. Do you mean they were lucid, but they believed they were living in a different year? Like thinking adults were still children in school and wondering when dead people were going to call? That kind of thing?
Stuff like "I'm your grandson, dadsnames kid" didn't parse at all, they said not to bring up shit like that so we didn't.
We had to move him into a house because he kept using his POW training to break out of the dementia ward. Pickpocketing keycards and shit, he was a badass till the end.