In case of accidents like that, the insurance covers cost as long the driver is the family/friend of the owner and was given approval. I have been with few insurance companies and all of them had that feature so I am guessing it applies most of the time.
 
If it's no body's fault and your fren is willing to give you $2500, why the heck are you still making a big deal? You were with that person in the car during the accident and you acknowledge it's not his/her fault. So, my suggestion is your fren is naive and agreed to pay you $2500. Just take it or else you will get nothing.