J.P.
I know it is different because my husband was so much older, but recovery from having your adenoids removed is very painful. He may just still be having pain and is afraid to eat. It sounds like you haven't tried smoothies, maybe add his favorite juice and see it that works. I would of course talk to your doctor since he is so tiny to begin with. But again it is a painful surgery and I bet it just hurts to eat anything. Poor guy!! Good luck and hopefully he will be fully recovered soon.