Yep, I agree with Roach. As a rule of thumb... As long as he is still roundish without being able to plainly see his backbone while laying down he is fine.
Don't try to feed him everyday. You could be causing more stress. Don't handle or disturb him any more than you have to. Just keep fresh water and do minor cleanup. Try feeding once every 7th day and he will eat when he is comfortable.
Force feeding is a last resort and should be done by an experienced person.