My Brother Is 31. We Were Just Coming Home From

My brother is 31. We were just coming home from working on our new store. He started laughing just a little but then needed to cough. He apparently couldn't cough and went into a raging snort and like he could breathe but then he acting like he had a seizure with his eyes rolled back into his head. He is obese but could you tell me if you think it might have been a seizure and what could have caused that?