I don't know how your dragon is coming along, but you might also try ornacycline its for birds. I was told by someone it is good for reptiles. I gave some to mine and it seemed in a few days she was doing great. ....mix In with water...or baby food ...he may have been fed outside of his terrarium ....also petco sales a vitamin mix I think which helps stimulate eating habits..
god luck hope he gets better