Another question: Can the insurance company from his company accept a settlement without us approving it? Or would they use subrogation and our insurance make us an offer then get reimbursed from them if we accept?
I have never been low-balled by the insurance company. I think they are more interested in settling smoothly-no back and forth and no lawyers-than trying to save $ by low-balling. In my last case, the adjuster didn’t even look at the car-the repair shop gave them the estimate. Since that was a bit over the published value of the car-I got the money. 
I really liked that car. OTOH, I tried to point out that the car had brand-new tires and after market window tinting. They assured me that all their settlements assume new tires and tinted windows…
That said, their final settlement was amazingly close to my total cost for the car. I think I ended up $200 in the red on a $20,000 settlement. I was quite satisfied and surprised by how close those folks got to the actual paid value of the car using just typical numbers. As far as I know they didn’t make any effort to customize the settlement. I got what the published formulas said.