My Mother is 73, has Alzheimer's and sleeps12 hours a night, she is not in end stage. Is it OK for her to sleep this long?

Seems to go with dementia. My wife, 78, is following her family tradition, and just this week has started taking naps, something she never did since about 1948. She sleeps soundly at night, 8 hrs., but now about another 90 minutes sporadically through the day.

I think it is a fairly common occurence. My mother is 86 and she sleeps about 14 hours a night and sometimes takes a nap. She goes to bed around 11 and gets up around 1 or so. If she is still sleeping at 2:30, I wake her up.

My mother, though much older than yours, sleeps easily 12 hours a day. I'd let her sleep unless you have a reason for wanting her to get up. My mom is easy enough to wake up for appointments, etc. So I let her sleep. One day recently I finally did wake her up at 12:30! Usually she's up around 10:30 and goes to bed around 9:30.