if you were injured and received medical treatment you have a claim against the other driver's auto ins carrier. The offer will depend on a lot of factors: how hard was the impact; do the bus cameras show your movement when the crash happened, what treatment did you receive.
It depends. If a one car accident, then most likely the driver wil be held accountable. If more than one vehicle was involved, there is chance that one of the other drivers may have been charged with fault. If so, your son still has a claim for medical payments through the ins for the car he was in.
I highly recommend that you consult with an attorney on your particular situation. During the consult you will learn the commong pitfalls, your rights,etc and be in a better position to make a decision.
There is not enough facts to do that. An attorney would have to sit down with your son and a copy of the file and from there come up with a rough estimate of potential value. Of course, ever insurance carrier evaluates a given case on a different basis. We never know what a jury will do. Especially when the defendant is the client's father!