I suspect the fact that he was fortunate enough for his mother to choose to migrate to the software capital of the world just before the dotcom boom probably had more outstandingly positive influence on his chances of starting a successful software business than any negative impact a part-time job as a teenager or his father choosing to remain in the Ukraine could manage.

Trust me, as determined as he's undoubtedly been as an adult, a teenage Jan Koum didn't cause the Iron Curtain to fall or the US to be accepting Jewish Ukrainian refugee families at that time and offering them welfare, and the average wannabe immigrant to the USA has absolutely zero chance of repeating that feat