I got a huge grey cats from an ad in the paper...he's very antisocial and getting thin, now he's got a brown crud seeping and drying up near his eyes and I am noticing that his nostrils are getting brown too from this crud. He's very very thin now and won't eat and he doesn't meow much. At first he seemed happy now he's just sick and depressed. I can't afford the vet costs, what can I do???