It's been over 20 years since I got hit, and I found out recently that one of the reasons I couldn't ride the bike I was hit on was because I was so tense when I rode it my whole body ached afterwards. I would think about the accident several* times during each ride.

Everybody is so different in their reaction to something like this, there can be no advice anyone can give you. But the one thing I'm sure of is that there is absolutely nothing* you can do. You can't push this one way or the other. There will be a time, maybe, when you give him the "get back up on the horse" speech, but if you do it too early he will assume that you just don't understand what's going on with him.

You're his Dad, so whatever you end up doing will be the right thing to do... Remember when your son was young, and he chose between you and his mom to ask questions or get advice? It was because he know how you would react and he knew that he needed what you had to offer. At some point, he will come to you, and then you will know exactly* what to do, and you will be a great help to him.