Liability for Accident

My father was involved in an auto accident where he passed out while driving & hit another car. The driver of the other car was hurt pretty badly & has sued. My father's insurance company has agreed to pay the full amount of his policy, but the injured driver is suing for an amount above the policy limit. My question is whether in NY, this is essentially a strict liability type of claim or negligence. My father had never passed out before & had no reason to suspect he might & the hospital he was taken to after the accident did not identify any cause (or didn't try to). Does any of this matter under NY law or is the fact that he hot the other car alone enough to make him liable?

I'd appreciate any information anyone may be able to provide.