Welcome! Thank you for your question.
Unfortunately the 401k benefits are payable to the estate, therefore they will be subject to the "five-year rule," meaning that all benefits must be distributed out of the 401k within five years after the decedent's death.
An estate is not a "designated beneficiary" so the life expectancy payout option is not available for benefits payable to an estate. The employer may not under stand it but the estate can transfer the inherited 401k to an inherited IRA for you, but that will not extend the payout period beyond five years. The IRS has ruled that an estate cannot "disclaim" retirement benefits payable to it.
I cannot provide you with legal advise. I have provided you with information about the law related to your question. My answer, and any information that you find online, should not take the place of having a consultation with a lawyer in your area to advise you regarding your specific issues.
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