Worst case scenario will be Do Kwon going in the US and facing the US court of law as we all know that they love to put people behind bars specially if it is about crypto exchanges, but we will see.
However, if he goes to South Korea and then penalized and found guilty and put to jail, I think he doesn't need to go to US anymore, I reckon.
So we will have to wait, this drama has been dragging more at least a year now.