TurboTax appears to not recognize the death of a filer when calculating the expected EIP/stimulus amounts, even though TurboTax has the information. Example: TurboTax correctly determined that joint filers should have received $2400 during first EIP. However, did not recognize that one filer had died prior to the second EIP (even though the date of death was requested at least three time while answering other questions -- why more than once>), and so calculated that should have received $1200 instead of the $600 actually eligible for. Simply answered "yes" to receiving $2400 + $1200 to prevent TurboTax from adding an extra $600 to refund that wouldn't have been legitimate.
Someone who passed away in calendar year 2020 and is otherwise eligible can receive both EIP1 and EIP2. So the $600 for EIP2 is correct for the decedent.
you figured out how to decline the EIP2 but there was no reason to do that.
You should go back now and change your response.
For deceased individuals see the second question under Eligibility. If they died in 2020 they still get it.