Can we buy a ticket and leave or will we be detained?

If your family member departs after she have overstayed her visa for more than one year, then she is barred from lawful immigration for 10 years unless she can somehow qualify for a waiver/pardon.  Many are disqualified even with family in the U.S..  If she returns to the U.S. in spite of this 10 year bar, she can be permanently disqualified from lawful immigration. As a result, I strongly recommend an appointment or teleconference with a competent and experienced immigration attorney before she decides to leave.  This way, she can make sure that she is doing the right thing.  She may decide that she must remain in the U.S. to avoid the permanent bar on lawful immigration that is triggered from such a departure.  The above is general information, not legal advice, and does not create an attorney client relationship.