The green card will stay with the person; only a judge can rule to take the card (a piece of plastic) away.
“If you stay outside of the United States for one year or more and did not apply for a reentry permit before you left, you may be considered to have abandoned your permanent resident status. If this happens, you may be referred to appear before an immigration judge to decide whether or not you have abandoned your status.”
If spouses filed taxes as MFJ for five years, it may be an argument to prove in court that you maintained your residency.
If the person’s green card has not expired yet, they may try to return to the United States.
If the person has a reentry permit (I-131), there should not be a problem.
If the green card expires, the person may contact the US consulate for a reentry visa (may be denied).