Congrats and these people are really lucky. Risking just $15 and receiving more than $15000, what a luck it is. 1000x the bet value. During this bullish season it is more than enough for the guy to spend good. Anyhow he needs to be careful to have an exit point at the right time. If not the same can dissolve in a short.
I cant say that he is risking $15 only as I believe he played many spins first before hitting that big win.
We can say he is risking just $15 if it was the only one bet he made.
It is not impossible to get huge win on first bet but it is a very rare case.
Still, it is a nice win no matter how much he spent before he hit it, even if he lost more than what he won on that bet, at least he got something back to his balance.