If that's what he thinks, it doesn't sound good. He sees no need to improve so he will not improve. And if he's reading these boards, he's a getting a lot of support and confirmation that the problem is with the coaches and not with him. So why should he try to improve?
He doesn't know where the coaches are getting their opinions? You have to be kidding. They see him every day in practice.
Sounds like a big problem.
Does the quote "He needs to grow up" ring a bell?
Never argue with an idiot. They will drag you down to their level and beat you with experience!