Ask your "knowledgeable" friend to finish the rest of his story.....The people in the know, the commercial tire experts, will tell you that 99% of what he said is pure sales propaganda, nothing but hype.
Are they LT, yep and that is what you should be running. Are there RV tires in your size, nope. Do so called RV tires have anything different in the compound that truck tires don't have, nope, pure myth....Of course the folks on the street that have absolutely NO knowledge about how tires are built will mouth the sales hype and perpetuate the myths. There are several actual tire experts on this forum that tried many times to give people the truth and facts, but finally gave up, as the typical RVer knew more than they did.