I am in need of legal advice. I am, along with my 16 year old grandson, being sued for an accident that my grandson was involved in while driving.

My grandson was driving my vehicle, without permission, and had an accident in my car. I was told he hit a mailbox, and another vehicle. I was told the female driver swerved and went around my grandson to enter a private driveway, consequently, the accident occurred. It was raining that day.