Aww, Pofi! I'm glad he seems to be improving, even if with resistance! I once cared for two IGs who would only eat if I hand-fed, or put the canned food directly on their (nonporous) kitchen floor. After a while of coaxing with their regular set up, I just started trying different things and that was the only way to get them to eat. Same food, same temp, etc., but just different feeding method worked for them. You could maybe try different location, too?
If he likes the jerky treats, would he'd like the boiled chicken with a little bit of seasoning, or maybe seared on a pan? I think it's great that he eats *something*, but it'd be easier for him to take in enough fluids if he'd eat wet food.
Hang in there, LM+K!