Then I commend him for that decision. As long as high school season is "in season" the other things can wait ... High school season is just 16 weeks long and that leaves, in essence, 36 weeks for other soccer (club, ODP, etc.) ... I'm all for a balance, but you cannot miss high school for club in-season.
I know many disagree with this and under certain circumstances (with plenty of advance notice) I've allowed players to participate in outside soccer, but not in the heat of the season ... One of the things you have to stress commitment ... Kudos to the coaches that emphasize this principle.
