Mental health

Looking for feedback on dealing with the mental stress my kid is going through after the current round of tryouts. He had a spectacular season as a goalie, helped his team get promoted, and was nominated by his coach for most improved player. But the stress he is going though right now after now making it to the 2nd round of mls next tryouts and probable demotion to a lower team is hard to watch. I keep trying to be positive for him and remind him of the "when one door closes, another opens" cliche but I worry about the toll it's taking on his mental health.