It's his own fault for not getting council at the appropriate time.
I was hounded by California tax collectors over a mistake they made, it was clear they weren’t going to listen to reason on how they were obviously wrong given their own documentation and a lawsuit was going to be my only recourse. I opted to just give them the money, it was far less than the cost of a lawsuit. I consider it a cheap lesson in dealing with California tax collectors something I never want to risk having to do again.