Son borrowed car and let friend drive-friend hit someone

My son is a licensed driver and insured under my policy - he's 17. He used my car yesterday and, unbeknownst to me, let his friend borrow the car. The friend hit a pedestrian and sped off. When my son found out he went to the scene of the accident and called the police. I'm freaking out here. My son got a ticket for allowing someone without a proper license (the friend is 16 and has a learner's permit.) The friend was arrested. I'm worried that my insurance is not going to cover this -they have yet to return my call. I am a single mom and do not own a home and have no assets. In fact my company just closed down after 30 years and I am getting by on unemployment. I'm afraid, considering the circumstances, that my insurance will not cover this accident and I will be sued. I have no money and don't know what I'm going to do.