Cracked head on LT80

My brother was riding his quadsport 80 at the track today and it started running really funny,so he comes in and we check the quad and where the exhaust bolts on to the head there is a crack on both sides of the exhaust mount on the head. A pretty big crack to,not a hairline. Just wondering if this has happened to anyone and why? He didnt ride for very long either so I dont think it overheated. I think because that mount on the head is the only thing holding the exhaust on exept for the rear of the exhaust mount so all the weight is on the head. Could I possibly get this welded to avoid buying a new cylinder head? Thanks.:)