This is really a non-issue. Are HS kids sometimes really mean? Absolutely. Do I think this kid was imitating a seizure? Prob not, his flopping does look like a fish as opposed to just vibrating like a seizure would be. Is this kind of distraction allowable at HS games? Sure why not. They do this at the college level and that’s where this fan section got the idea for creating a distraction. And he’s not directly under the basket as far as I can tell from the video. If they are chanting unsporting stuff of shining lights in the eyes or giving obscene gestures then deal with that. This distracting isn’t a big deal IMO.