Where do I get answers to all my situations with MIL on cleanliness and meds?

She refuses to bathe, won't wear pants...refuses to take diabetic and other meds. She urinates and poops herself. I am very small and cannot lift her and her son is always working outside of the home. We can't get her to go to the doctors, she just wants to die. Where do we begin, we are so frustrated. What groups or agencies do I contact for help. I also work full time away from home.