Good on him. My only defense is that it must be demoralising to play under a coach who seemingly doesn't have any time for him. At 21, as your first experience in the work force, no one can tell me that is going to help put your best foot forward. My hope is that he can improve and the coach can also improve him by showing some encouragement and building his confidence.
At some point, the lack of improvement in our younger players has to draw a line under someone's name at the club who has some responsibility for their development.