How much should advanced AD patient sleep?

When a person with advanced dementia wants to sleep late or get back in bed and sleep later in the day, should that be allowed or should they be required to get up and sit in their wheelchair?

My cousin has advanced dementia and is in Memory Care Unit. She is wheelchair bound, but verbal. She can still feed herself, but requires help with all other areas of her daily life. She has many characteristics of late stage, except she still is verbal and can feed herself. She has recently been losing weight, even though she eats well. She is not on Hospice.

I know that the staff get her up early and get her ready for the day, give her meds, bath, breakfast, etc. Sometimes, she resists and doesn't want to get out of bed. I think they work with her to convince her to get up. Should they insist or let her sleep in?

I've noticed that all but one of the dementia patients I see at the unit, are up and either in chairs or wheelchairs. (I suspect the one who is in bed is on Hospice.) Is this normal? Is there any benefit to getting them out of bed and up for the day or should they be allowed to sleep? Isn't this the body's normal way of declining? Do you only let them sleep as long as they want when they are on Hospice?