Answer: In my
humble opinion at the high school level there are attributes other than
size that I would consider far more important - speed, skating ability,
stick handling ability, conditioning, coachability just to name a few.
Some coaches (and your son's coach seems
to be one) might get hung up on size but I would think those coaches are
in the minority - however he is the coach and he is the person who
ultimately decides who will be on the team.
Obviously as the level of play increases
size can be a consideration because hockey is a very physical sport but
even then I believe there can still be a place for the good, aggressive
small player - the NHL is full of them.
Unfortunately, I doubt that you have any
recourse at this time.
I assume your son played in a youth
program in the past and he may still be able to play in such a program. If
so it would be good to encourage him continue to play outside of school.
He may experience a growth spurt in the next year or so and if he
continues to hone his skills he may have another opportunity to impress
the coach. In any event he will be able to play and enjoy the game.