https://www.irs.gov/newsroom/questions-and-answers-about-the-third-economic-impact-payment-topic-b-e...

The IRS only states -

A payment won’t be issued for someone who has died before January 1, 2021.

Since your brother passed away after January 1, 2021 he was eligible for the third stimulus payment.

sorry for your loss.    Normally, a taxpayer will qualify for the full amount if they have an adjusted gross income of up to $75,000 for singles and married persons filing a separate return, up to $112,500 for heads of household, and up to $150,000 for married couples filing joint returns and surviving spouses. Payment amounts are reduced for filers with incomes above those levels.  so if the AGI test was met for the month he was alive in 2021 he would have been qualified for the payment and you as his heir would be entitled to cash the check.

@Mike9241 and @DoninGA 

Thank you both for your answers. as part of my research before posting, I visited that IRS link, and found the same info under the question about if a deceased individual will receive the payment. My question with their response is it  seemed to only focus on spouses. My inclination has been that i can deposit it, but wanted some confirmation if I was reading the IRS correctly. I can undersstand the IRS going ahead with the payment to a surviving spouse, but to another family member doesn't make sense to me. But if the gov wants to provide the money i'll take it. And yes, he qualifies based on income. Thanks again.