BobbyJ, first of all I am so glad you got to see your granddaughter! And you got to put your recovery tools in place. But then got the verbal vomit, oh my!
And I call it that because that's usually how it happens - just open your mouth and spew all over someone.
Remember how I brought up triggers? You are a trigger for her right now. You won't always be, but right now, you are. And she is hurting. And she needs to be validated.
Who would you tell me to believe? My daughter? Or my drunk husband (her step father)? I think you already know the answers to the questions you asked here. And its ok. You still are a great Mother. You are also a human being. Who makes the best judgment calls she can with the information she has to work with.
I think counseling is a great idea! It will allow for a facilitated sharing of the past as well as learning some new tools to deal with each other better in the future. Good for your daughter for suggesting it! She is doing her own work...