What do you mean by "filed as a widow."

2020 Would have been Married Filing Joint, since spouse was alive at some point during 2020.

Unless she has a dependent child, 2021 would be filing status Single.

With dependent child, would be "Qualifying Widow".

Next question's - Did they notify the administrator of the death of the spouse, and still got like one payment in the spouse's name at the start of 2021, If the administrator issued payments in the decedent's name all year, that might be a red flag to do more digging as to whether there was any kind of estate work done regarding the spouse's death, or whether someone needs to deal with that now.