The mounting tabs on the standard bumber are not particularly thick. I would be hoping they were the weak point in the accident.
The accident may have been sub 15mph. Any faster and with that rapid deceleration, hitting an imoveable object, your mate would have left his teeth in the steering wheel.
The dilema is
Tell insurance, investigate, find no damage, make no claim, but the insurance still class you as have had an accident.
Investigate, find no damage, all hunky dory.
Investigate, find damage, make claim, get the runaround from insurers