Didn't see where your Buddy has a Class III or Class IV hitch. that makes a difference.
Your friend doesn't NEED a weight distribution hitch with a 3500 truck and a TT. But he probably needs it for his receiver. Receivers have two ratings typically.... One for weight carrying and one for weight distribution. The weight distribution rating is typically much higher.
If he is going to go without weight distribution he needs to make sure that the receiver is rated for the tongue weight.
I too am new to the idea of a WDH and have been doing some research. The statement above is why I am picking one up for my TT.
My NTU TT specs sheet says is
just over the rated 500lbs tongue weight for my Trucks class III receiver, I drove it home from the Dealer without a WDH and it handled fine so thought I was safe BUT.... Figure in the weight of batteries and full propane tanks added to the tongue that were probably not included in the factory specs... your friend will also need to consider the weight of any cargo in the bed that is BEHIND the rear axles. Add to that any cargo in the camper AHEAD of it's axles and maybe even a bike rack or Gen set... it all adds up.
Like I said, I am all new to this and may be out in left field for your friends application. But I am picking up a WDH rated at 750 / 1000 lbs.
