Welcome mobumpkin, I'm sorry about how your sister is treating you and also your parents. Unfortunately, many JWs treat DF'ed and DA'ed JWs poorly, because of the WTBTS's shunning doctrine.
Were you and your sister close when you were a JW in good standing? If you were close, then may be her cult persona feels threatened and needs to over-compensate to keep her authentic persona in check.
Since you have close JW family and friends, you will never be free from JWs trying to coerce you to "return to Jehovah". Fortunately, you can do independent research of the WTBTS and how the WTBTS uses BITE control techniques to victimize JWs, so that you can heal emotionally and get rid of WTBTS induced phobias. Also, you may learn how to communicate more effectively with JWs so that they can critically think for themselves, instead of blindly following WTBTS's doctrines.
Have you read any cult-exit counselors' books, such as Steve Hassan's books (i.e., "Combatting Cult Mind Control", "Releasing the Bonds: Empowering People to Think for Themselves", and (his latest book) "Freedom of Mind: Helping Loved Ones Leave Controlling People, Cults and Beliefs"), visited his website www.freedomofmind.com, and watched his FREE videos on his website? I would recommend watching the following videos on Steve Hassan's website: How Big is the Phenomenon of Undue Influence? (2:01) and Strategic Interactive Approach explained 2003 (1:23:23). Also, have you visited other reputable websites like www.jwfacts.com, www.watchtowerdocuments.com, www.jwsurvey.org, www.freeminds2.org, etc. to learn more about the WTBTS?
Peace be with you and everyone, who you love,
Robert