You really can't blame the kid for being angry. But please remind him that he has his whole life ahead of him and that statistically speaking he would have never gone pro unless he was almost superhuman all through high school and college (sad, but true).
I blamed mom for about 1 day then got over it and went on with my life and family of course.
One thing to keep in mind though, and for anyone else who will find themselves in the same position of facing angry children; it is our responsibility as parents to thoroughly investigate any organization prior to joining it and dragging them along.