It depends on the EXACT wording of HER beneficiary designation, who owned the policy and her state of residence now and at the time of divorce.
Normally beneficiary designations in life insurance policies are written so that if the named beneficiary dies, the insurer makes payment to the insured/policyholder's estate. (The insured is normally also the policyholder owner, but if not it can get interesting.)
Assuming she was both the insured and the policyholder, and there was nothing in her divorce decree specifying that her ex was to remain a beneficiary, then the heirs she named in her Will (if any) or her heirs at law (if no Will) would inherit the proceeds.
If someone dies without a Will the estate typically is divided among one's spouse and children in some proportion, based on the deceased's state of residence.