The first thing that needs to be done is read the IRA contract. It very likely sets out default beneficiaries in the event that no beneficiary is selected, the chosen beneficiary is dead, etc. It may be that if the named beneficiary can't get the distribution it might go to someone other than the beneficiary of the decedent's will. So the beneficiary or estate executor will want to know that before spending a bunch of money pursuing this.
You were given good answers on the other forum (and you omitted details that would have given TM a better chance to answer you). If the beneficiary is absent/missing, then indeed you can petition the probate court to resolve the matter.