Yes he is natural. He is still young and works VERY hard. Besides, The IBJJF now randomly tests Male Black Belt finalists (anyone in the top 3) as well. As much as he competes, it would be very difficult for him to cycle on and off and get the timing right. And since he is almost always top of the podium, he is guaranteed to get tested. They are using the Olympic banned substance list as well, so it is very strict. He still competed this year, but notably some others where suddenly absent.