My dad's cat has been around for a long time (18 years). And over those years he has had some pretty noticeable health problems. He is very skinny but has enough food and he does eat. He is so skinny he looks emaciated! He gets thinner and thinner and has had this problem for at least 4 years he doesn't have any coat problems or anything like that. He is now so light I (being not very strong at all) can pick him up effortlessly with one hand and he still feels like 3 pounds. Someone said he might have a thyroid problem...also may I say he is almost completely deaf. It takes the loudest sound for him to turn his head and this hearing issue has developed over time. I know old cats lose some hearing... but really; that much? Also my dad NEVER takes his pets to the vet as often as he should. Right when he gets them he takes them to the vet once to get dewclawed, vaccinated, etc. I will persuade him to take my beloved childhood cat Sugar to the vet hopefully once I know what might be wrong with him because there is almost no way for me to know. Please help!!