RMD- owner deceased and so is primary beneficiary

i put this out here once before but struggle with the right answer. 

I have a participant over age 72 that passed away in 2020.   Non owner –  The RMD was waived in 2020

His spouse (beneficiary) passed away in 2021.  She was over age 72 as well.   Money is still in the participants name in the plan.

The plan is terminating, assets will be rolled over to an inher IRA

The 3 children are the beneficaries.

RMD is required for 2021, based on 12/31/2020 value.

I am trying to figure whose age I would based the RMD on.  Owner?  Spouse or oldest child?  Any thoughts?

Thanks, I appreciate your help.

What was the his actual date of death and when was her actual date of death? Just curious to see if the Beneficiary Designation date comes into play. And did the spouse make a claim for the account. 

Participants death was July 2020.  His spouse passed in April 2021.

The accounts were still under his name. 

Thanks!

Because she passed prior to the BDD, you would use the oldest beneficiary DOB for RMD purposes.