nitenurse, did you say he was smoking "legal"weed? is there anything else, bathsalts at all? that legal weed is dangerous, the synthetic form of thc they add to it is garage cooked. that has to go first of all. the kind of siezure you describe sounds a lot like the result of "powerhitting". thats when you take a huge hit and hold it in while crouching and someone else either squeezes your chest or even worse they will put pressure on the arteries in your neck as you stand as fast as possible leaving you twitching on the ground.. its intense and can be scary to watch. those are some things you might want to see if hes in to. it could be something else clearly, i myself am prone to headrushes if i stand too fast when i smoke i think most tall people can be. either way, id suggest if he has to smoke something stick to weed but on the condition that you get him looked at, maybe a mri or ct scan. he may just have a sensitivity to thc hopefully but the only way to be sure is for to get checked out and stay away from everything but herb. and if he does have an issue with thc there may be a way around it or he may just have to give it up.