Can I refuse to continue to be my father's caretaker?

Can I refuse to continue to be my father's caretaker? My father is 55 years old has many health issues. He has had one leg amputated, a kidney transplant, uncontrolled diabetic, high blood pressure, vision problems, mental problems at times, chronic diarrhea and has lost all control of his bowel functions which makes him dependent on diaper use. My wife and I have been caring for him for about 3 months after being discharged from a rehab place. We thought this would be short term but he is unwilling to participate in his care. We have a very long list of medicines for him daily and it takes us about an hour to get him to finish them all because he does not cooperate with taking them. When p.t. comes he always has an excuse as to why he can't do it today. The aide comes once a week to help wash him up and he doesn't let her do anything because he is afraid of getting cold. My wife and I have 3 small children and it is a strain on us in every way possible to continue to care for him. He does get a small SSI check but that does not go very far as he takes a lot of medications and his diaper supplies are costly. He has to have a heater on 24 hours a day, the TV on, as well as the light always on. We live in Michigan so it is cold here, but the rise in the electric bill is a fortune, not to mention his laundry which is 2-3 loads per day depending on how big of a mess he makes using the bathroom in his pants. He has had several trips to the hospital for falls out of bed; thankfully, he hasn't ever gotten hurt. Always has UTI infections because of this. He is not always a pleasant person to be around, either. We are trying to refuse to care for him any longer but that doesn't seem to be an option because he refuses to go anywhere. This story could go forever because he never lived with us before. He came up to Michigan for a weekend visit and got ill. He lived in a different state before this and was married until this happened. So we are stuck in a place we can't get out of, but we need help from somewhere. Last thing is our three year old daughter was recently diagnosed with severe asthma because of his smells that are hard to cover up with air fresheners, which is what caused her problem. She has been rushed to the hospital three times in six weeks because of not being able to breathe. Someone please help us.