Inherited IRA

Our friend’s uncle died 12/18/22 and was taking RMD’s at the time. Our friend’s date of birth is 3/18/85.

He just found out 11/12/24 that he was the surviving beneficiary. The first listed beneficiary had died, and the custodian just tracked our friend down.

The way I understand it, as long as the account is actually properly setup by the custodian by year end, he will have to make RMD’s starting with 2024 (2022 & 2023 were waived). If he only wants to do RMD’s, does he start with the single life table factor and deduct one each year with year ten taking out the full balance? If not what is the formula?