Ugh. That's -exactly- what Norm(n) looked like when I got her(him).
I can't remember if you said in your other thread if he'd seen the vet yet, but I'd have him seen and dewormed.
My kiddo hasn't refused a meal in the two months I've had him, and sheds out fine now, so they can certainly recover from a state like that! Big kudos for your rescue.