johnj-
Find a good place to sit, open up that folding chair, tear open a bag of seeds, make sure the sunglasses are clean, and enjoy the show.
In all seriousness the process is now in the eyes of the coaches and the hands of your son. Tell him to be "who he is", always give 110%, and take no prisoners. Things will work out, and in the end if he accepts the results, shows he's a team player, and if he has a smile on his face doing that, he will be a coaches dream. What more could a parent ask of a Freshman?