Poor Charlie. He's not eating because he can't smell his food. If he's on dry food, try offering canned, the smellier the better. If you still can't entice him, try heating it slightly in the microwave. I guarantee this will stink up your kitchen, but it may get the molecules moving just enough to make their way to his nose buds. If nothing else works, try cooking him some chicken and softening it up to cat food consistency in a blender. By now you have probably already heard from your vet, but since this works for lots of sick cats, I am posting anyway in case it helps someone in the future. Good luck with Charlie, and I hope he feels better soon.