When the beneficiary and the executor both pass away, does the unclaimed life insurance stay in the wife's estate or does it go back to the father’s?

Any attorney would need to see the entire will and would have to know what state this is being probated in. However, assuming this is NC, then here is what I think would happen: Father died with a will, but the will contained a survivorship requirement such that mother would have to survive by 90 days. Since mother did not meet this requirement, mother is treated as having pre-deceased father such that mother's share of father's assets will pass to father's alternate beneficiary, i.e., his son or anyone else named as a contingent beneficiary in the father's will. Your post also indicates that the executor died. I assume that the mother was the executor and that you are referring to her. However, life insurance proceeds are a non-probate asset. Which means they do not pass via probate and are not subject to any 90-day survivorship requirement. I would need to see the beneficiary form, but my guess is that the life insurance proceeds would be payable to mother's estate and distributed as per her will or the intestacy laws. Possibly the assets would pass to a contingent beneficiary if named. It would only be in the event that mother actually died before father would the insurance benefits go to father's estate.