Im not trying to fight his claims, I was at fault, Im just trying not to end up with 15k of bills to pay, which sounds like it might be my insurers job to sort out.
just leave it in the hand of your insurers that's what you paid them for, take whatever hit there is to take and move on - but make sure you mention the claim to your present insurance company otherwise your policy might be void.
it's already spilt milk