My X has some family that blame he and his sister b/c they were the ones faced with the awful choice to have to turn off their mother's vent. She was having major organ failure and likely would not have made it, and definitely would never have become conscious again.
His crazy aunts blame them, bad mouth them, make up lies, it's horrible. The ICU actually had to have them escorted out of the hospital by security. Point being, my X and his sister had to literally cut out all contact w/them. The pain of the loss is so much already, to have someone blame them is too much.
I hope you evaluate your relationships and if someone is being toxic to you, which clearly threatens your sobriety at this point, cut them off and don't listen to what they have to say. I am so sorry for your loss. The best gift you could give to your mother and yourself is your sobriety.