My son is exactly in the same boat as yours: 16 years old, 4 catchers on his summer team, became the starting catcher for his varsity team midway through freshman year at a small private HS. His primary for 4 years has been catcher, but he is also competent in the outfield.
He gets some time behind the dish, but on a rotating basis with the others who are also competent catchers. He probably gets far more time as an outfielder, averaging an extra 2 games during the catching rotation. Another factor in his being put in the game more often is because he is batting well at the moment (roughly 435 average/ 590 OBA) and is one of the faster base runners on the team. Even when he is sitting out a game, he is usually put in as a runner for the catcher or pitcher.
Bottom line: I think you do get to play more when you are hitting the ball and play another position, because the coach has more options for you and looks for ways to keep you in the lineup. At 16, unless you are a pitcher, it's probably in your boy's best interest to know more than one position. JMO.
The hard part might be convincing him his mom knows best!
