This reminds me of a doctor we had when I took my wife to the emergency room one time. First, the kid looked like he was Doogie Howser's little brother, and second, the only muscle he had developed was his biceps. There was no definition anywhere else, just these giant biceps. I've never met anyone who skips not just leg day, but also the rest of arm day.
This may come as a surprise to you, but there is an entire world of strength training outside of Rippetoe and his texts. Maybe, just maybe, he's at the point where he doesn't have to set up like Rip teaches for BEGINNERS. And why would you say no Valsalva? Maybe he doesn't do the whole "take an exaggerated breath while making a funny face". Also to consider, training his deadlifts might look different than a lift in competition.
This should go in the "really makes me mad thread," but I am surprised by coaches at all levels that will see a kid performing a sport with bad form and not correct him. For all the "work hard" and "be tough" that coaches mouth, when it is time to put in some hard work, they too often just slide by.
I'm not criticizing the guy. I guess it's just pointing out impressive feats using different techniques. By contrast, this guy uses a technique more akin to the SS setup, which, given his size compared to others who pull this kind of weight, suggests he has a very efficient method of pulling: