Too bad it's already been debunked...
Given that Omar and her siblings all came to live in the U.S. under identical circumstances as refugees, and that Omar herself became a naturalized U.S. citizen while still a minor, how did one of her siblings end up with such a radically different immigration status that she would have needed to marry him in order to facilitate his U.S. residency application?
Also, if Ahmed Elmi were truly Omar’s brother, why would he have needed to take the drastic step of marrying her in order to secure a path to U.S. citizenship? U.S. Citizenship and Immigration Services (USCIS) policies qualify immigrants as eligible to apply for permanent residency status (and later become naturalized citizens) if they are the “spouse of a U.S. citizen” or the “brother or sister of a U.S. citizen.” Why would Omar commit a federal crime and risk a prison sentence (and possibly her own citizenship status) in order to provide her brother with the opportunity to apply for something he would already have been eligible to seek? (Snopes)