Keep this in mind, your son has been invited more than once to these tryouts. There are many players who would love to be given even just one shot at the Area Codes.
Yes, it's hard because we are all conditioned to believe that if our son doesn't make the "next step" or isn't on a certain list then others are "passing him by." The reality is that there is always going to be someone who is better, and the other reality is that none of us know how this is going to end. All you can do is try to enjoy the fact that your son is playing a game that he loves, and help him get to play it as long as he can. If he's having fun playing, then it doesn't matter if he wasn't selected on the Area Code team.