Dear Navy
I know this is an older thread. I hope you see my response.
When we come from a particular family culture, that becomes our "normal." It also affects other choices we make in life, like friends and spouses.
If that family culture was dysfunctional, such as alcoholic, and we start recovery, the old "normal" doesn't work any more. A result of this change is the realization that we have surrounded ourselves with people who fit the old "normal." This is painful and awkward, because now we have to choose who to associate with. Sometimes this means losing family and friends.
You sound like you are at a place in your journey where you realize that your child deserves better in life than what you got. Grandma will prove to be a toxic influence. It is time to move on.