Good points made in posts above:
twotex:
"Different pitchers respond to different things."
True. Basically, if the pitcher indicates to your son that his input is not helping him... then it's not.
Emanski's Heroes:
"Besides, what are the chances that your son (or any catcher at that age, really) truly knows enough about pitching to spot flaws and make the proper suggestion for adjustment."
I agree, it would be unusual for a freshman catcher to recognize mechanical flaws correctly AND be sure that the advice applies to this pitcher.
Julie