Does your liability insurance cover medical for a person if you were not driving?

Your liability insurance does not cover medical expenses in your vehicle no matter who is driving. Depending on your state and the regulations there, this could vary somewhat. Liability is coverage for the party and passengers in a vehicle that you hit if you are At Fault. If you are talking about a person in the other car then yes, but if you mean a person in your car the answer is no. You need to purchase "Medical Payments" or PIP coverage to provide medical coverage fro those in your car.