Multi-car policies and owner liability

What is the name of your state? What is the name of your state? New York


My friend's parents share a multi-car policy in both of their names (let's say "Insured A" and "Insured B"). There are three cars on this policy, each owned individually by only one of the two insureds. One of the three cars on their policy was involved in an accident last week which killed their 18 year old son (the operator) and injured his passenger and the driver of the vehicle that hit him head on. The vehicle involved in this accident was only registered to Insured A (the wife and mother). If the driver (Insured's A son) was liable for the accident, will Insured B be at all responsible for any damages awarded in excess of the policy limit if the case goes to a jury verdict? In other words, is it the operator and owner of a motor vehicle who are potentially liable for damages in excess of policy limits or operator and any insureds named on a multi-car policy?