Im so sorry youre stuck in this situation. Its good that youre so concerned about your sister, but you cant control her. You should talk to her, and if she doesnt stop its not your fault at all. If she knows shes caught, and cant stop herself from her bad behaviors, its a sign that she really does need help. Try to not make it sound like your attacking her, because then you could just scare her away. The best thing to do would be to open those lines of communication with her. If nothing works, you need to ell your mom. If you need anything, message me