Please accept my condolences on the loss of your father.
If your father did not have a will, he would have been considered to have passed intestate. What this means is that the state law would determine who would inherit his assets. Under Oregon intestacy law, if he was married and had all children with his wife, she would inherit everything. If he was widowed, then everything would pass to his children. A family member would need to file a petition to open a probate case in order to administer and settle the estate.
If your grandfather has your father listed as a beneficiary, then when your grandfather passes, any inheritance will pass to the same beneficiaries that inherit from his estate.
Only your grandfather can change his will.
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