I have a $74,000 2019 Ford F150 King Ranch, max tow, 3.5L with every added option possible and a 13,800 tow capacity.
I also have a 28' Coachmen Apex 289TBSS camper.
And I have a 2019 Ram 2500 6.4L.
The Ford with all of the HD engine and towing options is not even remotely comparable to my RAM 3/4 ton. The Ford was special ordered by me, line by line, to be the absolute highest tow rated F150 I could get made since I got rid of a F350 diesel and bought the F150.
Your son has a back assward towing setup, to make it sort of work.... he will need an absolute top of the line weight distribution with integrated sway control system.
Starting at the Equal-Izer 4 point at the lowest end I would recommend and going up to the ProPride or Hensley.
Anything with the add on sway controls is a useless joke comparatively, I've used them in the past. The only advantage of those add on brake pad type sway control bars have that they are dirt cheap.... But they barely work at best. Consider them worthless junk in this particular case because this situation is way upside down.
He really needs a much more serious truck, but since he has the baby Ford, he will need to crutch the severity under built and under equiped truck with a high end sway control system. Don't save money, but the very biggest, baddest and best WDH/SC he can possibly muster. Maybe it will work out. It's not going to change that fact that his truck has no business at all ever being attached to that size trailer.
Tail wagging the dog is an understatement here. Surface area is massive on that trailer.