What Causes Dizziness And Body Tremors?

My boyfriend was sitting in a chair getting his hair done he says to me I feel light-headed he puts his head on the table then goes to lay in the bed. Two minutes later he goes I m ready I say you sure I m good. I go to finish his hair but, his head drops I sit him back in the chair his eyes rolling back in his head, he starts shaking, he acting like he s not getting any air(gasping) I rub his chest put cool water on his face he acts like he going to catch his breath but his eyes pop wide open and he snoors hard and loud. I put a little more water ,talking to him, he starts to come to then back out finally he sits up dazed then says in a drunk voice I m ok just need to lay down I put the fan on him and in a few seconds he was fine like nothing happened to him . It s not the first time what could it be.