"the IRS waived required minimum distributions (RMDs) for inherited IRA beneficiaries in 2021, 2022, and 2023, and again for 2024 which might mean they will waive them permanently."
Absent some unforeseen reason, the penalty for failing to take a beneficiary RMDs that circumstances require be taken under the 10-year rule will not be waived for 2025. The IRS waived the penalty for 2021 through 2024 only because the regulations resulting from the SECURE Act had not been finalized by the end of 2023. Those regulations are now finalized.
To see if individual retirement accounts are mentioned, be sure to also search the trust document for the word 'retirement.'
If the trust document does not otherwise address IRAs and the term qualified retirement plan as used in the trust document does not include IRAs, it does seem that the IRA, or the income from the IRA, is to be divided equally among the beneficiaries. Unless a sub-trust is established for each beneficiary under the terms of the trust and the girlfriend is disabled or chronically ill, it appears that all beneficiaries would be subject to RMDs based on the age of the girlfriend, requiring the IRA to be fully distributed in substantially less than 10 years. If sub-trusts are established for each beneficiary, presumably the IRA would have to be subdivided into a separate inherited IRAs, one for each beneficiary. With sub-trusts established, the inherited IRA subdivided, and your sister disabled or chronically ill, only your sister would avoid fully distributing the IRA by the end of the 10th year by being an EDB treated separately. (Even if the girlfriend qualifies as a disabled or chronically ill EDB permitted to be treated separately, the girlfriend's share of the inherited IRA would be required to be fully distributed in substantially less than 10 years because of the girlfriend's age).
