You are a saint !!!
If that were me, I could never talk to her again, if my mom did that to me or my siblings. She is damn lucky you and your family even look at her. You are a SAINT Your grandparents are too, for giving you some stability in your life, that is nice to have fond memories of times spent with them. I wish I had something to say. But I will say I'll be thinking of you, and wishing you well with all of this.
Take care,
"darkeyes"