I wouldn't tow with it, not that 5er...he has hardly any GVWR on the truck, but guess he can use up all his RAWR, seems the way it's done now a day's. but if tires only air to 35 psi, doesn't sound like he has "E" rated tires which I'd recommend. Sounds like a truck you would run from light to light to take to the grocery store, or haul soccer equipment in...don't think I'd hitch the 5er that is being talked about up to it. But if he has already done it, why does he want information NOW?? One of those, "my mind is made up, don't confuse me with the facts type thing"....
I would say it's a Crew Cab...truck in sig makes 3rd "crew cab" I've owned and if OP's is a 12" crew cab" it's bigger than a "club cab" I think
I'd look at one of those little Scamp 5er's, or get a truck that one would actually use to tow with..even another 1/2 ton that is actually set up to tow would be better, but if they have a 12', doubt they're going to buy another truck