It doesn't matter, tell him to continue to improve/get better. The situation may seem as a setback but it's a big character builder..........find the positives and forge ahead. Be the best teammate, best ball shagger, the best __(insert)___________................control his attitude and effort. The pieces will fall where they fall as you can't control others and the decisions they make.
I will continue to repeat, attitude and effort! It's very difficult to turn away a player that has a good attitude and works his tail off.
Don't compare other players tools, attributes, ect. It's irrelevant to your sons development as a person and a player. Be consistent working on his own game, energy focused for ONE second on another player is time away from his own improvement.
By taking ownership in his own journey, not blaming others and really focusing on the things he can control, that being attitude and effort.