Meg, the not eating and perhaps also not drinking enough will cause a lot of the problems too. They need nourishment regardless, to make the brain & rest of body work with any good affect.

If your Mom is worn out, then I'd say she is about done in herself. You don't need 2 people to care for 24/7. Get things oranized so Dad can take the next step. Mom can easily go visiting if they are both still in the same facility, but perhaps 2 areas of it. She needs support for her care to be able to move away from caregiver to individual. As a senior, she will have naturall slowed down, she needs to recuperate. Help her make the choices. Help by bringing a meal every time you come to visit. It will be one thing she need not have to do, in her overwhelming day.
-Sharon

Talk with your parents about getting a diagnosis for Dad. He will likely need a diagnosis before being accepted into the residence's memory care unit. It sounds like your mother needs the support.

Welcome to this caring group. As an RN I think mom's mental and physical health is at risk and dad should go into memory care asap

He has Frontal temporal & Alzheimer's. Diagnosed Oct. 2019. Dad doesn't reason or understand anymore.