My grandfather adopted my father when he was 2. He then divorced my grandmother. He didn't have a good relationship with my father. Once my father had us we never seen or heard from my grandfather. My question is if he disinherited my father does that apply to me? Also do I have any legal right to his estate?

If he left a will then his estate will be distributed according to the terms of the will. If there was no will then the laws of inheritance apply. In that case you may have a claim.