The 800 will put a real strain on the truck's rear suspension, due to the fact that it will most assuredly push right past the truck's RAWR by itself, plus the fact that the COG will be about a foot behind the rear axle, shifting a bunch of the truck's front end weight on to the back axle too.
In short it will not be pleasant even if you make the typical mods like LT tires, airbags, and helper springs. Pure weight issues notwithstanding, this is a PHYSICS issue that no amount of add-ons will cure.
Add to that, Palominos aren't all that well built, and odds are the 800 is designed to be supported by 6'6" of bed, not 5'6". That unsupported foot could prove to be an issue somewhere down the line, in the form of a sagging camper.
He'd be much better off with the models specifically made for his 5'6" bed, though he will still be overweight.
Putting 10-ply tires on half ton trucks since aught-four.