Immediate relatives include:
The spouses of U.S. citizens,
The children (unmarried and under 21 years of age) of U.S. citizens,
The parents of U.S. citizens at least 21 years old, and
Widows or widowers of U.S. citizens if the U.S. citizen filed a petition before his or her death or if the widow(er) files a petition within 2 years of the citizen’s death.