Although I sympathize with your plight, and from what you described the kid needs a good kick in the ass, I think this is a loosing case. In the end it will be his, and his buddies, word against yours. At best it will be a no fault accident, at worst they will hold you financially responsible and magically the kid will have a few thousand worth of medical bills. My .0002 cents, drop the case and learn from the experience.