Mom with dementia is 76 pounds, not eating much and excessively sleeping. Has anyone else had these concerns or issues with a loved one?

My mother has dementia, was diagnosed 6 years ago with early onset. She lives with my father about 30 minutes from me. I am her legal guardian, I have her spend 2 nights a week at my house so she can attend a senior day out program. She seems to be much less alert and has been sleeping excessively in the last 2 weeks. She is a heavy smoker and both her and my father smoke at home together which makes it difficult to get her to leave her "cozy" home. She has always been thin but is down to 76 pounds as of the last dr. visit this week. We live in New England and winter is here so she is cold all the time. Freezing not just chilly. I am concerned as she seems to be sleeping so much more in the past couple weeks. She had a heart attack in March and had a stint put in. All of which she does not remember at all. Trying to help her eat, smoke less and try to bath at least twice a week is becoming difficult. There are concerns with her kidney function and she does not drink water at all. I have scheduled a series of tests to check her heart stint in the coming weeks. I am just concerned that other issues may be going on with her internal organs. Has anyone else had these concerns or issues with a loved one with dementia? Thank you in advance for any advice.