I have a snake who seems to be territorial. He's a grump in his tank but fine when I finally get him out. My solution is to use a snake hook to pick him up. He seems to "get it" that when he's picked up on a hook, no food is forthcoming and he should remain calm, though that took a little bit of practice.
Edit: also, there is no shame in wearing leather gloves for awhile until you get "re-acquainted" with him and his habits. If you (or your son) are tense and afraid when handling him, it can make the snake more tense and afraid as well. Sometimes the gloves give that little extra bit of confidence someone needs to be able to comfortably get used to the snake again.