I have one more suggestion...just a guess...but snakes with internal discomfort don't have any way to know what the problem is, they just lash out. You gave
him antibiotics for a month or so...but did you think to follow them with some reptile pro-biotics (like Bene-Bac) ? Maybe he has a tummy-ache? Are his stools
looking normal?
Have you had his stools analyzed for anything else that might be going on? Parasites can ruin anyone's day...