How long was he allegedly in the hospital. If he was banged up well enough to have clot(s), he would have at least been admitted to the hospital and not just treated in the ER. Most people who have been in good crunches usually have a difficult time getting around because they are extremely sore for days.

I'm still having a hard time with what your are trying to find out. Do you doubt the accident happened, or do you know that it happened, but you don't believe your "friend" was involved?

I guess the bigger questions would be why would a "friend" of yours make this sort of claim? Or, if he is your friend, why would you doubt him and why such a big deal?