Entering USA after expired re-entry permit

[Duadiya]

Hello, My parents re-entry permit is to expire soon but due to conditions not in their control, their return to usa is under consideration. We all are looking into options.what options do they have, if they do not manage to visit usa before the permit expires?

If they delay their visit for another 1 or 2 years, with a valid green card and expired re-entry permit, will they be able to enter usa. Is their any procedure available to facilitate in such situations.

[newacct]

The options are:
1. Fly to the US on their valid green cards, and hope that the immigration officer will feel that they did not abandon residence and waive the documentary requirements. Or, if the officer does not waive the requirements, and your parents refuse to voluntarily give up their green cards, they will be placed in removal proceedings, and they can hope that they can convince the immigration judge in immigration court that they did not abandon residence, and let them in and cancel the removal proceedings.
2. Apply for an SB-1 returning resident visa at a US consulate, which requires proving that they could not return any earlier due to circumstances beyond their control.