I had my green card since 1980 but kept my Russian citizenship. Two years ago my Mother took ill and I returned to Russia to help her. She recently died and now I want to return to USA. The problem is my green card has expired. Can I use the expired card to come back?
No, and you’ll have some serious problems in regards to maintenance of your residency. In order to maintain your residency you should be present in the US for half the year or more or have a very good reason for being outside for so long. One way is to apply for a reentry permit before you leave but it doesn’t sound like you did that. You will need to either apply for a returning resident visa or obtain a letter from the Consulate to give to CBP when you attempt to reenter.