The nude videos leaked around late 2017 or early 2018. I remember seeing this video months before I saw any nudes, and this was posted to Instagram in July 2017 when he was at least 19 or even 20 depending on which month he was born in. His Instagram says now that he is 22, so he sold those videos when he was 19/20 years old, definitely not underage.
He is just trying to stop people sharing those videos. But in my opinion if you are willing to sell your nudes on the internet, then you are willingly taking the risk of those nudes being shared around. If you can't take that risk, then don’t sell your nudes.