I really like the diet suggestion a lot. I have lots of reason to believe in it very much. If it takes too long watching for what things to remove, maybe try a zero-diet (boiled parsnips and water with no herbs or salt) for a few days and build one foodstuff at the time from there. As soon as something gives a reaction, remove it. Children do not get lack of vitamin issues quickly enough for this to be a problem if you keep expanding the diet.

The VERY WORST one can do is going on and off meds all the time like the dad not giving it to him. It is far worse than not having them. The meds suppress things that come out all at once even worse because the sudden lack of meds creates a new chemical imbalance in the brain. Plus the kid takes another couple of days to get used to them again. If he is so opposed to meds (which, incidentally, I agree with) he should come up with other workable solutions instead, discussing them with you first, and only implementing what you can agree on. The last thing a troubled kid needs is inconsistency.