As long as they died in 2020 the worksheet is correct. 

so the estate is then entitled to the credit?

yes

Whoever is entitled to the rest of the refund gets it. 

You probably tried to find the answer to this question here, before asking, but you should realize that it is asked about four times a day.  And the answer is in the 1040 instructions, as well as the law itself, which is in plain English.  I'm just curious, if you are bothered by someone dying in May, what would not bother you?  Someone dying December 29?  Or would that bother you if the $600 was not paid?  We had a question earlier in the day about someone who died in mid-January 2020. I suppose that would really bother you?  But we don't write the laws.  it's fine to share opinions about them, as long as this doesn't short-change our clients.  And your client generally is the person who pays you for the return, and maybe a Form 1310 to collect the refund.  

Thanks Bob for your answer. The reason I am bothered is because this is for my mother-in-law. We don't need the money. It doesn't make sense to me. In addition, we got a stimulus check for my mom in April. She passed in 2018 and we had to return the funds. 

"In addition, we got a stimulus check for my mom in April. She passed in 2018 and we had to return the funds."

Because the payouts are Advances, projected using 2018 or 2019 tax filings. Then, the 2020 Actuals is the reconciliation for what you are entitled to against what you got already.

So, of course, Mom doesn't qualify, but MIL qualifies.

"We don't need the money."

Give it to your Food Bank.