In what year did your father pass away?
In what year did your mother pass away?
The answers to these questions are needed to determine if the IRA became owned by your mother by default. If it did become owned by your mother by default, the IRA custodial agreement may provide for a different default beneficiary than the default being your mother's estate.
Has it been less than 9 months since the death of your father?
Did your father name contingent beneficiaries?
Regardless, unless the IRA custodial agreement says otherwise for these circumstances, the IRA inherited by your mother and be transferred intact to an inherited IRA for the benefit of your mother's estate and from there split into separate inherited IRAs for the benefit of the estate beneficiaries. There is nothing in the tax code that prohibits this. In some cases the IRA will be transferred directly to inherited IRAs for the benefit of the estate beneficiaries by the direction of the executor, skipping the intermediate titling.
