Let me state this very clearly. When it comes to protecting your family for danger, in my opinion, karma doesn't matter. If someone is coming after my family, I will take the karmic backlash to protect them and stand behind what I do. Black magick is black magick. Black magick always comes with a karmic debt. Do you accept taking on that debt for your family?
Before turning to black magic though, try doing a modified version of the binding spell we gave to Carol from Stafford against the abusive man in your mother's life.