In the end there will be a judge that reviews everything. The auto insurance may pay, depending on the policy. Judge will determine that. He will also determine who gets money and who doesn't. Either way, it's not her problem. She has insurance on both sides, they can fight it out in court, but it shouldn't fall on her.
What he said. BCBS and the Auto insurance company can fight it out over who should pay but ultimately it should be one or the other. Just because they disagree doesn't mean they get to just opt out and dump the whole bill back on her.