Yes, it is an "interesting" dilemma.   I have seen the arguments for both sides, the bill said overpayments did not need to be returned and no provision to pursue overpayments but the IRS issued guidelines the overpayments are to be returned and set up a special process for people to return the funds.

The taxpayer is 83 years old.  I am inclined to advise him to hold on to the wife's overpayment and wait for someone to ask for it back.  More than likely he won't be around by the time that happens as we know the IRS does not operate at warp speed, especially these days!

We will request EIP #2 for $600 on his 2020 tax return since he received zero and see what happens.