If he is driving on 80 psi, he need hard rubber tires.
I never hesitated to buy Chinese tires especially that when it comes to trailer tires, there is no much competition and was always very pleased.
Not saying the above tires are Chinese as those days tires in US come from all odd places.
Just bought backhoe tire made in Sri Lanka.
Also 16-ply can be pretty misleading rating as new 14 ply can have higher load ratings than older 16-ply.
So don't make any general assumptions. Go to the tire place and read the prints on the tires.