I'm the Mom in our situation and I've been telling my son to pretend I'm dead for the past few months because someday, hopefully not too soon, I will be! When that time comes he won't have me on call, will have to deal with everything on his own. Please tell your Mom that you need to be able to outlive her, as awful as that might sound!
You ou might do well to find a roommate. My son is living alone and the only HUD housing that's opened up has been for a minimum of two people. He's living in a place (independently, with caregivers coming and going) that we own, but I would rest easier if he had a roomie.