I am at a loss. Is anyone giving him anything else? Did something stressful happen? This could be temporary this time.

Has his vet checked him for infections?

I'm fostering a cat that cannot tolerate chicken. She eats fish. She nibbled on some albacore tonight. Not much, but it was a start. Now I need to find a way to give her some vitamins. She needs lots of attention but doesn't like other kitties. sigh

Cats are such complex creatures. It sounds like he needs constant reassurance after 4 years in a garage.

Good luck.