Only an designated beneficiary roll a a 401(k) to an inherited IRA. Only an individual can be a designated beneficiary, so if the distribution is payable to the estate, no rollover to an inherited IRA is permitted.
Presumably the deceased was not married, otherwise the default beneficiary would normally have been the spouse of the deceased. Assuming that's the case, there is no avoiding this being a taxable distribution, no way to continue to defer taxes on this money.
