deceased beneficiaries of will and bank account

Grandfather died with will dated 7 years before death. Will Specified small amounts to 2 natural children (1 deceased now). Will also noted that some CDs exist with named beneficiaries. In last few years, all CDs were closed. But proceeds from some of CDs were put into a Payable on Death Bank Account and others were put into a personal account with no beneficiary. The Bank documents show that to claim POD account, that the owner (my grandfather) must be deceased and that beneficiary must be alive. POD beneficiary died 2 months before grandfather. Does this automatically go into grandfather's estate? Will only states that CDs owned at death should go to the named beneficiary and does not mention what happens if beneficiary predeceases grandfather.

Grandfather's will also noted that all remainder and estate residual should go to my father (step-son). My father predeceased step-father. My mother closed my father's estate with Final Order to Discharge from Probate. My father's will bequeathed everything to my mother.

Does the inheritance from Grandfather have to pass through my father's estate (requiring re-opening of estate)? I've been advised that it would not, and that in Georgia, the inheritance would go to my father's children, bypassing my mother entirely.

It would go into the estate if it is not payable yes.