父母有绿卡，到2025 年有效。 他们于疫情期间（2020年11月）回国，本来没想呆很长时间， 就没有办回美白皮书。 但由于疫情，通航原因在中国呆了差不多两年。 如果今年底回美国，绿卡会被没收吗？有无什么可以补救措施? 谢谢。
-Technically, the green card is void. So, it is possible to have trouble for your parents to use it to reenter US, depends on the IO at the port of entry.
There is SB-1 visa for them to reinstate their green card, but I don't think they can get the SB-1 visa because Covid 19 is not good enough as the reason which prevented from coming back to US on time for SB-1 visa application.
Your parents may just abandon the green card, then apply for the B2 visa to enter US. Then, you can sponsor them to apply for the green card again 90 days later after they enter US using B2 visa.
