With my parents, it was more like come-and-go symptoms of dementia, but there was no definitive diagnosis. After some time, I came to realize DF's symptoms were indicative of a UTI, and DM got confused when she was on a heavy dose of meds.
We were able to keep DF at home, but even when he got confused he was never mean. His face always lit up when he saw me. Also, he couldn't run away as he lost the ability to walk. Importantly I had enormous support from DH and DS#3 who moved in with DF. And we also hired a home health aide (trained in the Philippines as a nurse) so his physical needs were met. So basically there were always two strong men around to do what had to be done. I "supervised", gave him his meds, cooked, scheduled and attended medical appointments, fed him some of his meals, dealt with medical care providers etc., but DF was much larger than I was, I had (have) a bad back, and I never would have been able to change diapers/ bathe him, etc.