What Will Happen for Her Green Card If She Wants to Live outside U.S. for Long Time?

Question:

My mother has U.S. Green Card, and she wants to live in her home country for a longer time. What will happen for her Green Card if she wants to live there for more than one year?

Answer:

Many people want to apply for U.S. Green Card for their parents, and hope it will facilitate easy travel and long visits for their parents. But their hope does not fit with U.S. immigration laws, which require that the Green Card holders should make their permanent home in U.S., not in their home country. Also, there is no minimum amount of time that a parent can live in the United States to avoid the problem of "abandonment of residence" of United States. 

If a parent with Green Card leaves the United States, even for a short time, and upon return the border U.S. officials can be convinced that the parent's real home is outside the United States. So, the official can deny the parent's entry into U.S., and revoke the Green Card. Also, trips outside the U.S. of 5 months or longer are guaranteed to raise series questions, and trips of a year or more can raise a presumption that the parent has abandoned their residence of United States.

http://www.greencardfamily.com/question/question2017/Abandonment_Residence_010417.htm

http://www.greencardfamily.com/parent.htm