Deceased participant

One of the 401k plans that terminated, we were couple deceased participants and since they were no beneficiary the plan sponsor directed to cut a check to the deceased estate.  Although there was no estate set up, a check was cut to the estate of the deceased name.  the check was cut in 2023 and in Feb 2024 the spouse has reached out claiming for benefits, since the spouse wants the money to be rolled over, I'm trying to understanding how the tax that was deducted be handled?