[Kjesse]

You're going to pay here one way or another. If I were you I wouldn't let insurance cover it, pay it out on your own.

And your son might not have done it. That doesn't matter now though, the other guy is going to say things like, no ding before, ding same color as your door, etc. That's proof enough, given that you don't know (and apparently neither does your son) if your son did or didn't hit the door.

Now if you had no passenger, and he said you dinted his driver's door with your passenger door, you've got a case.

Sucks, but in case your son did do that, teach him to be careful when opening the door. This is all about making the best out of a bad situation at this point.