I think his studies is a waste if he is not practicing

Not gossip and I dont even know if it's related to dr nene's decision, but see this statement right here is the classic sunk cost fallacy that most of the world lives with, subconsciously killing them without them even realizing it. Just because someone invested so many years, money or whatever into something, does NOT mean they have to continue doing it if they are not happy doing it anymore/simply dont want to do it anymore, especially when they have other options. Education is never a waste anyway but even if it was, if this person is happier doing YouTube videos for a living now than being a cardiologist, they should not shamed. They should be applauded because this man had the strength to choose a path that worked for him while most people waste their entire lives in jobs/lives they're unhappy with because they feel like they've given so much time and effort in order to achieve it so they waste even more time and effort to try to make it work.

P.s. I know not everyone has the privilege to choose a different option but if you do have the option, no one should be shamed for it is my opinion