Wow, you've gotten really good advice from all of the above posts.
The insurer does get a market report, but this report likely does not secure vehicle List Prices, but what they actually sold for. Unfortunately, you are going to have to hustle a bit to get a good price for your vehicle and the price they gave you is, again, after the sale price has been negotiated.
I once handled total loss claims as a third of my workload. There is not much room for negotiation on these types of claims and the in-house adjusters know it. The ones I dreaded most were those that were upside down on their loan and expected the insurer to pay for it. God willing, I'll never go back! Chances are good that this poor adjuster feels the same way. I willing to bet that this adjuster dreads having to deduct the salvage from your settlement as he is under tremendous pressure to close these claims. Between you and his boss, he probably has no choice.
I won't excuse poor customer service, but these claims are tough and try not to take a price disagreement personally. They've got to deal with a caseload of at least a hundred cases like yours. I'd rather take another 400 Katrina property claims than take 50 total loss auto claims.
You mentioned that the carrier does insure your son, but if they are actually the third party carrier, then you won't have a case for bad faith due to the lack of contractual obligation. As for licensing, he may not need one since he's working for a licensed carrier. This was the case when I worked on staff for a carrier's branch that serviced three states- two of them required a license, but I was exempt.
Good Luck.