My Mom all of the sudden is sleeping a lot and hardly wants to eat. Any advice?

Talk to her RN at the nursing home. He or she would have a lot of experience with this. Has your Mother's meds been changed? Maybe they are too strong for her.

I doubt the sleeping a lot has anything to do with her 'beginning dementia.' Maybe it's a result of a recent medicine change...? A urinary tract infection, perhaps...? Chicago1954 has the right idea.

Doc may have also (in light of his diagnosis) started her on a mild tranquilizer which could be "relaxing" her right to sleep. ;) Check with the charge nurse on any new meds she's taking. Suspect those.

Probably meds. Make a list of all meds, dosage and time taken each day. Go over with nurse weekly to be sure nothing changes. Mother was never left alone in hospital or rehab and we verified all meds before given. Mistakes happen and would have happened to Mom had we not been so diligent.

Of course, check her meds. Often that could be it, but it also could be progression of dementia. When my cousin's dementia started progressing, she started sleeping a lot. I've read it's an indication of the disease. Does she have a diagnosis?

Does she communicate with you? Does she complain of any pain? Sometimes a person in pain sleeps more or it could be depression. Depression can make one sleep a lot too. With some people, when they learn they are losing their memory and capacity to function, they get depressed. It's not unusual.