some helpful tools that may assist him in dealing with this. OP could talk with him and use information from that article to help his son understand that feeling nervous is very common and that he isn't weak for feeling this way, and that even some top athletes have had to deal with this. However, if he wants to perform his best, there are things that he can do to help deal with how he feels to try to keep it from affecting his performance. I suspect that very successful athletes who deal with serious pre-game nervousness have also had to come up with techniques to address their anxiety. There are probably stories or articles online that describe what they have done.