The NHL took him at his word that he was innocent so they closed their investigation pretty quickly. I get the sense that since now he's seeking assistance that is available to NHL players and has agreed to be regularly tested as part of it, that the NHL won't do anything more at this time, especially since he was pretty much guaranteed a spot on the Russian national team if he was healthy any of those 4 years, including the 2022 Olympics, and that's embarrassing enough. But if he tests positive for something anytime in the future the NHL will drop a looooong suspension on him.
Of course, my speculation could turn out to be wrong.