Anonymous wrote:"new team coach has pulled out DS and 1 other aside to be GKs"
If this means that your son will be expected to play GK as his primary position, and he doesn't want to, then just tell the coach "DS would like to contribute his fair share of playing GK if the position is rotated around the team, but is not interested in playing GK any more than that." I would think that the coach would see this as a reasonable compromise.
GK is a tough one. While I've played sports where the coach's determination of where you should play is not open to debate (American Football comes to mind), soccer seems unique among the sports most kids play. GK the only position in soccer that is so substantially different than every other position, that it's tough for a kid who doesn't enjoy GK to be put into that role. To a player who loves soccer but doesn't love GK, playing GK can feel like you're playing an entirely different game.
For example, in American Football, there are dramatically different roles -- an offensive lineman's game is dramatically different than quarterback ... running back ... receiver ... tight end ... not to even mention the defensive positions. But in that sport, every kid is doing something "different" and, while a player may not like the position he's assigned, he doesn't feel singled out as the one stuck doing something different. Baseball is the same (and every player gets to bat); in basketball the positions are very similar.
Not to mention 99.99% of the time the Goalie position is never taught in team setting. It maybe time constraints but most likely although they a a licensed soccer coach. They have no training or clue how to teach the position correctly.