Both of my grandfathers were alcoholics. One was horribly abusive, mean, and just right downgrading to my mother, and the other abandoned his family, and left my father in the hands of my mentally ill grandmother. It is a miracle that neither one of my parents had addiction issues themselves. However, they did raise two good codependent children and in spite of their own upbringings, did everything in their power to make sure our childhood was nothing like theirs.
Just goes to show that there are very few degrees of separation when it comes to the impact upon families.