Yes, he had not filed his tax 2019 tax return showing his wife as deceased until after he received both $1,200 payments via direct deposit.

The recovery rebate credit worksheet is not set up to return overpayments.  I assume because if your stimulus payments were based on 2019 income and your income increased in 2020 to the level you would not be eligible, the IRS guidelines say the funds do not have to be returned.