This type of response is pretty common when an active addict loses their number one enabler--they will do or say anything, whatever it takes to avoid having to deal with the real problem: their addiction.
You do not need a front row seat to this madness. Cutting off all contact--including third-party/mutual friend contact and social media stalking--will give you the time and space you need and deserve to get some perspective on the abusive situation you have been living in.
And please don't be afraid to tell your family you are grieving. They can't understand why it isn't cut and dried, but stuffing your feelings to put them at ease won't serve you in the long run.