Oh my god, I am so behind the times. I had no idea that Cracker Jack was your new fur child

Before I go find your *other* thread , I agree about keeping an eye on him and calling the vet if you feel the need. It's a good sign that he's drinking.

Maybe some warm, smelly food like heated canned food will help his appetite. Our last vet always recommended 'mouse temperature' stinky food to perk a sick or stressed cat.

HTH