My Dad (95) sleeps almost all the time. Any advice?

MIL sleeps as long as we will let her.12-14 hours a day then eats and sleeps some more in her chair. I don't care but warm weather is here and I am not going to be quiet so she can sleep. I have to vaccum and clean in the cool morning or nothing will get done when it gets hot.

As others have mentioned, he needs to be seen, medically, or somehow assessed. However, before you do that, pay attention to when he sleeps. Some patients sleep all day and are up all night. Some sleep specifically during certain parts of the day or only when it's a dark day. Keep track of this because this information can be useful to pass along to the medical folks.

Is "almost all the time" 18 hours a day? 20? more?

When he is awake, is his dementia worse than it has been recently?

I am wondering if it is time for a Hospice assessment.

If dad is at home, at least ask the MD for a visiting nurse.

I see by your profile that your dad has Alzheimer's. Is he in the final stages or is this sleeping something new? I would check/call PCP. Do you have hospice in?