Does spouse need protection from parent who refuses to go into a home?

My spouse has cared for a spouse and grandmother for the twenty years that we have been together. Two years ago, things took a turn and both grandmother and parent became bed bound. Spouse did all possible still then washing clothes, changing diapers, running errands, doctor appointment, washing heads, feeding, lawn and house upkeep, etc. Then a back injury took place because my spouse already suffers from serious pain issues and depression. Grandparent passed a year ago but that still left the parent who is much more difficult to work with on a daily basis. The parent is highly critical, will not take medicine, constantly removes oxygen, refuses to eat on most days, and refuses to wear diapers, which means we constantly wash truckloads of clothes. Not only that, this parent wears the lifeline machine out, which means we constantly get calls all times of day and night to come and open the door for ambulance because on most occasions it is that the parent has gotten out of bed and fallen. Because of this difficulty spouse wants to get a key made and leave it somewhere on the porch for the ambulance people. We are not sure that is a good idea. Hospice was coming out twice a day and that system was so abused that now they only comes out once a day for only an hour. This parent lives alone. So on weekends we are on duty to provide care and every time the button gets pushed, this is about once or twice a week. Parent has been suggested to by hospice, by hospital staff, and by family, that nursing home is best option. However, that idea is angrily refused every time. We are also caring for my aging parents (80) and it is tiresome because I have to travel 30 minutes each way to care for them. At least with them so far it is just helping with cooking and meds setup. We have small children who life also seems to be on hold because we are on call for the problem parent. Some days spouse gets so uptight and depressed when the weekend nears. Some days spouse goes on weekend and says the house looks like a hurricane has hit, diapers either off and on buck naked, telephones and meds in bed and on floor, clothes everywhere and the house smelling from the truckload of laundry. We’ve tried contacting aging council, mental professionals both at hospital and outside of hospital, social workers with all saying since parent is of sound mind they cannot make them go to nursing home. So care is pushed back to spouse and some days spouse can’t get himself to do anything. Because of my past with parent, I will not go over to do for parent unless spouse is present but I will do the cooking, shopping, and laundry although it gets tiresome. So I’m wondering do we need something in writing to protect ourselves from the parent who says she will get us in trouble for neglect? We have two small children that we have to make sure gets their homeschool work done. At times, it feels that all we do is work and no downtime. I’m sure that’s our life – all work and no play.