I agree with TRHit's 1st post on this one: let the kid decide when he wants to talk. I would have hated it if my dad had tried to "coach" me after a horrible performance...I was too upset to talk about it, and I wouldn't have really HEARD his message anyway. He let me talk when I was ready...and it made all the difference.
It isn't a parent's job to have this post-game talk anyway. As a head coach, I've seen many parents force their kids to go over it, and I don't agree with it. Let the player (it's his performance in question anyway, isn't it?) determine when he's ready to talk about it, then support the young man. Don't try to solve everything, don't point out the obvious, and stay positive. It is very easy to forget that these are KIDS...and they need to know that a parent's support is unconditional and unwavering. Good night, bad night...kid still deserves respect and admiration for doing his best.
Once the kid IS ready to talk, listen before you speak. Let him talk about the parts of the game that HE deems necessary - again, it's HIS season and career, not yours.