If you are familiar with this American artiste you would know that he is a big time gambler or you can just say he is addicted.
In my opinion he is not addicted, he just likes to play and has the money to afford to play with high amounts and these losses do not harm him.
it's very possible that the casino allowed it to happen for promotion purposes. It could be a way of advertising their casino what do you think about that? It's just a random thought, It's also very possible that he just got lucky.
As far as I know the games are provably fair, so there is no way the casino can give him wins, the guy was simply lucky to win a lot of money, just as there are times when he loses money. The most important thing is that he is playing for fun and I really like him and how he is promoting the stake