Rob,
Your guy should get a broker who is a yachtworld paid subscriber to look up the reported sales prices of any similar boats sold within the last 45 days (no more than that because current market conditions make older sales not comparable)....that data is not available unless you are a member broker. That will get you somewhere in the ball park.
The truth of the matter, however, is that at this level of boating, the condition of the boat, hours, service history, local demand where the boat is sold, and the dealer's financial situation all are more meaningful in figuring what the boat can be purchased for.
Each Marine Max store "owns" its inventory and the local manager makes the valuation and pricing decisions on trade-in's and sales prices respectively. If this is the only 40+ft DA or EC in the area, it will be higher than a MM store that has 2-3 similar boats. I've been involved in 3 boat deals since August with MM stores in 3 locations and all have been more negotiable than I thought possible and all were quite eager to work with the buyer on repairs, add ons and thrown in services.
If your guy is phone shopping direct to the Clearwater store, my guess is that he has not convinced them that he is a serious boat buyer yet.....and he probably won't until he writes a deposit check.
As far eating the cost to ship the boat from Florida to NY is concerned, y'all just need to get past that one. No dealer needs to sell a boat that bad. If the buyer won't run the boat there on her own bottom, then he should be prepared to handle the shipping cost.
Hope that helps.............