My 13 year old daughter is a brat Help?

Your daughter seems to have control issues, however, this can be traced back to thye source, which is you. You are not doing your job of being a good parent, and allowing violence is just physical abuse and is going to turn her into a more violent person. Also, a BIG problem is, where is her FATHER, look up the statistics, children are alot better behaved and do better in life when there is both parents involved in their life, and your sister has no idea how to raise children, and should be reported to child abuse services if she keeps threatening to "beat her ***". Be a parent, and quit bitching about your stupid problems online, ask a therapist, cause obviously, you, your sister, and your daughter need one A.S.A.P