The amount of money he wants to spend is going to play a major role in the ultimate decision but the GVWR of the fifth wheel and the construction quality should be major considerations. Personally, I don't want to tow more than the 14,100# of my trailer.
I recommend your son consider the HitchHiker line manufactured by NuWa Industry in Chanute, KS.
NuWa Industries, Inc. .
He can spend more, or less, but the build quality of a HitchHiker can only be beat by a Teton, Newmar, Travel Supreme, or New Horizons, most of which went under when the economic recession started because sales stopped dead in their tracks.
Nobody in the industry can beat the customer service provided by NuWa from CEO Mike Mitchell who routinely participates in discussions on the NuWa Owner's Forum to the regional sales managers who provide the factory tours and now sell units direct to consumers from the factory. Also included in the exceptional service are Laurie, the interior decorator, who will return phone calls and discuss interior fabrics and colors, Rose the parts manager who now operates a parts store and will ship whatever an owner may want or need, the engineers who will respond to phone calls and emails regarding designs, weight, etc. and the best RV service department in America, run by "RV" the service manager and Daryl Dennis, shop foreman. I often pull my trailer 550 miles to Chanute if I want something done because they are the product experts and I always leave feeling that I got more than I paid for. Their labor rates are the same as RV dealers but their times billed for each job are a fraction of the time an RV dealer will bill for upgrades or repairs. Mike Mitchell is a smart businessman. I suspect he works with RV to make the service department the best kept secret in the RV industry because it builds prospect interest, encourages customer loyalty, sells lots of trailers, and generates considerable repeat business.
HitchHikers are now priced at wholesale price direct from the factory. See the inventory section of their website. That is not bogus, it is a fact. When I bought my '07 they weren't selling direct from the factory so I negotiated a near wholesale price from a Kansas dealer. Now the factory sells at similar prices.
I believe HitchHikers are now the only RV product built using very dense and strong blue Dow corning styrofoam panels. (Not ordinary whites styrofoam but blue. ) Teton formerly used that method also in their very expensive all weather trailers but Teton is now gone from the market.
I am high on NuWa products, not because I own the brand, but I own one because I am enthusiastic about the product. I took Bill Stockard's advice and considered NuWa when I started looking. I did my homework before buying. The purchase and ownership has been an excellent experience. They are well built, very well insulated units of sound and sturdy construction. Not the cheapest, but among the best built.
My final comment is this: advise your son to look and consider very carefully before he buys a unit with Lippert frame and suspension which is most of the Elkhart brands. I won't name them here because it will offend owners who are satisfied with their products. If you or your son care to PM me I will say more.
George "grizzly" of TDR has an RV buyer's product guide book he generously shares with TDR members considering a new RV product. Grizzly will tell you or your son what his guidebook says about particular brands.
And, by the way, 6,000 lb. axles are too light for most modern fifth wheels. 7,000 lb. axles only add another $100 or so to unit price if he orders a new one rather than buying from a dealer's lot. Ditto the large Dexter brakes. They provide far better braking for only a couple hunded dollars added to the price.
Attention: TDR Forum Junkies 
