Apparently he coaxed him to give his best and reminded him that "this is not you. I've seen you play many times". Something to that effect. This is aboveboard and perfectly OK in my opinion. Yes, it was not his role to do that. But his alternative would have had to formally warn/penalize him for 'tanking' if he didn't start something. Now that is a serious warning that too in a grand-slam tournament. So he informally checked if he is OK, realized the kid was pouting. He had a few kind words of encouragement. The crowd got a real tennis match.
People are acting as if he forcibly injected PED into the kid. This nutcase is the biggest waste of talent since Nalbandian, Safin and Tsonga.