The best option is to set up a payment plan in the interim with the insurance company of the vehicle that he struck and then immediately turn around and file a law suit against his own insurance company for insurance bad faith. Unless he was grossly negligent in how the wreck occurred, his insurance company is supposed to pay for the damages that he caused. They may drop his future coverage, but they are liable to pay for his damage caused to the other vehicle.
As such, based on what you have shared with me, he needs to file suit against his own insurance company. In the interim, see if you can negotiate a payment plan with the other party and remain faithful in his payments. If they will not allow this to happen, then he may have to file bankruptcy, but that should be a last ditch option. Moreover, he should not do that unless he is successfully sued and he has not other route to take.
Most companies will negotiate a payment plan after a while...particularly if they believe the person is going to file bankruptcy and leave them with nothing to show for it.
He should definitely sue his company for insurance bad faith, even if he does file for bankruptcy.
Let me know if you have any other questions.
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Best wishes going forward!