NOP, I told my family of my suspicions, and a number of the facts. They know that she was involved with him, but they don't know the depth of involvement. They know that she has backed off from her involvement to some degree. I chose to partially expose to them because I know that if my mom knew the whole truth, it would be even more difficult to get M into recovery. If W felt like she had enemies in my family, she would see forgiveness as an even more difficult prospect.
Maybe I am off the mark here. They know enough to not blame me for all of our current probs, and that was enough for me.
Conflict is treated like a communicable disease in W's family. Once you touch it, you are tainted. Scared to speak up is a good way to phrase it.