One of my friends who is US Citizen (born in US/white) married a Korean girl, but one time when they travelled they came back to US separately and the US immigration officer thought that the girl might be a suspected fraudulent case so they denied her entry. So my friend actually had a buy a ticket for her to go back to her country. She was pregnant at the time and now she also had a baby but immigration is still not allowing her to come back.

Anyone have any idea on what can be done?