What you stated is correct. You need to look at the death certificates to determine which parent died first (look for time of death.) The second to die is likely the only beneficiary of the first to die. You need to look carefully at the will or trust to determine who the beneficiaries are and they should appear on the 1041 showing their share of any distribution. They would likely get a K-1 showing no income to report, since I would expect no distributions had been made for 2023.