My first priority would be to have the player talk to the coach and try to fix the situation. He is going to have to deal with personality issues with other coaches, coworkers, etc. for the rest of his life so it is a good idea to learn how to deal with it effectively. If he gives this a legitimate effort and it doesn't work, then you might have to look into other options. I know of a similar situation where a potential D-1 player was benched for the majority of his senior season (don't know why, didn't ask) and ended up having to go JuCo. I heard that D-1 coaches had called the HS coach to ask when the player would be pitching so they could come watch but were told that he was suspended without any reason given.