What type of exercise can be done?

Medicare will pay for in home physical therapy when prescribed by her doctor. The therapist can show her and her caregivers exercises that are doable for her situation. My dad has had this for the last few months and it’s been good, though he’d be the last to admit it!

Yes, there are exercises that can be done in bed or in a chair. Get a PT to show you some that Mum can do safely.

Even those totally immobile should at least get range of motion therapy so they don't get contractures. Before she went to the NH I had my mom doing some very simple chair exercises - it helps with circulation if nothing else.