My parents having un-expired green card travelled to India last year January to close all the ties in India and return back to USA. But unfortunately my father had health issues and had to go through a surgery and couldn't return back within a year. I would like to know what will happen if they return back now? I see that the option to apply for reentry permit is not possible, since they are not present in USA. Is there anything else I can do? Any help is greatly appreciated.