@poorchip - maybe I missed whether this part was answered:
<<Is an RMD required in this situation, how is the amount calculated, where is the distribution reported, and who pays the tax on the distribution?>>
1) the 2021 RMD was required and is based on the IRA owner's situation (your father in law).
Take the balance of the IRA as of Dec 31, 2020 and divide by the factor in the table in the link below. Use the BLUE column as that was in effect in 2021.
Look up your father-in-laws age as of his birthday in 2021, even if he died prior to his birthday.
So the number you are going to divide by is going to be 8.1 or 7.6 (96 or 97 years old) depending on his age on his 2021 birthday. That result is the required minimum distribution from 2021.
https://static.fmgsuite.com/media/documents/62a03f4e-4470-466d-ab38-c2d1850bfc7d.pdf
2) that amount needs to be distributed from the IRA in 2022 to the Estate as it is the beneficial owner of the IRA and pay any tax required. Follow @Opus 17 's advise as he makes some very valid points.
3) there is also a 2022 distribution required separate from the 2021 catch-up distribution.
