Let's call your client John and the late wife Mary.

in 2022, Mary withdraws a large amount from her IRA and gives it to ... John's family?  And they are estranged from her, or John, or both of them? Not that it makes any difference.  

But now John is executor of the will, so presumably responsible for filing Mary's final tax return.  And taxes are owed.  And there are assets in Mary's estate that will pay Mary's taxes, unless there are priority claims ahead of them.  (Like statutory family allowances, final expenses, and administrative expenses.)  

Not filing MFJ is a no-brainer.  Mary's final return is MFS, and if John doesn't know whether he should pay taxes or pay claims with higher priority, he should ask his lawyer, not you.