adderall is a stimulant but is not know to effect blood sugar as far as I know, but you might want to double check that with the pharmacist who can look up this interaction in his system.
It certainly sounds like a drug reaction. Did she respond positively when the medication was reduced, and if that did not happen, then maybe you should suggest a trial of reducing the medication.
You already received the best advice from Jaquta and Paxiled...He should see his doctor and he should never smoke weed again..period....The chances are very strong that the weed influenced the seizure..