My husband had borrowed a friends truck (friend A) to move some items. Another person was at our house (friend B) eating dinner. My husband backed out of our driveway in friend A's truck and hit friend B's car that was parked behind it. Friend B did not want to file on his insurance because he was worried about being dropped by his insurance company due to previous accidents. Friend A did not want to file on his insurance because it was a work vehicle. We could not file anything on our insurance because our vehicle was not involved. Therefore friend B got an estimate on the damages to his car. My husband payed friend B in full the amount that was shown on the estimate to fix the repairs. We called the body shop to check on the repair status & found out friend B never repaired his vehicle AND the amount of the estimte was lower than the one friend B had given to us. Since there weren't any insurance companies involved, were we responsible for the damages & were we obligated to pay the full estimte even though friend B was receiving a discount through the body shop? Is friend B obligated to fix his own vehicle since we have paid him in full the amount of the estimate?