Resolved Question: Deceased father has deceased grandmother as beneficiary on life insurance policy?

My father recently passed away and on one of his life insurance policies my grandmother was listed as beneficiary. She is also deceased. I am his only biological child. There is no spouse but there is a step child. I live in minute and he lived in iowa. Do I need to go through a probate lawyer? Do I need to become head of estate? What needs to be done for taxes? I am lost and looking for a direction to head