You can ' t force somebody to cut an abusive person out of their lives . They simply have to get to that point themselves . Your grandma is probably old enough that she just doesn ' t think it ' s worth it to end this relationship she ' s held up as important for so long . But that doesn ' t mean he has to be in your life or your mom ' s or aunt ' s . Let your grandma know you won ' t be coming to anything he is invited to , and that you are happy to have grandma over for all holidays . You can even adjust your scheduling so that she can do something with him and something with you if that is what she wants . Also let her know that she doesn ' t deserve to be treated poorly and that part of the reason you are doing this is that you can ' t stand to see her take abuse like this that she doesn ' t deserve .