My mother in law has a himalayan who is 11 years old. The past 3 months he has started developing scabs that puss. She has been to the vet multiple times and nothing has helped. She has changed his food. She is always up to date on his flea medicine. He is an indoor cat. She just noticed when she cleaned her closet, where he has been sleeping, that he has been laying in his own poop and pee. The doctors are baffled. Do you have any idea what we can do?