From the Draft Instructions:
Generally, you are eligible to claim the recovery rebate credit if in 2020 you were a U.S. citizen or U.S. resident alien, weren't a dependent of another taxpayer, and have a valid social security number. This includes someone who died in 2020, if you are preparing a return for that person.
https://www.irs.gov/pub/irs-dft/i1040gi--dft.pdf#page=58
