<<<<<<<<<<HUGS>>>>>>>>>
You've been through a lot, no mistake! To help you to understand the depth of narcissism: they do not acknowledge accountability for the damage that they inflict, unless they are willing to recognize that they are a part of a horrific cycle.
You are not responsible for the actions of others, your sister, included. You have endured an enormous amount of loss, trauma, etc. The best possible course of action would be to seek the help of a psychotherapist or counselor that specifically addresses domestic violence and abuse.
Not all narcissistic relationships are between men/women or husbands/wives. Thanks for YOUR post - it gives credence to others who have suffered similar abuse from siblings!
God bless and good luck!
My abusive narcissist blamed his mother, hated his mother, and inflicted damage upon his mother - his father was the abuser and narcissist and he learned how to lie, manipulate, and damage other human beings by watching the fear (which was equated with "respect") that was instilled in his mother.
Yes, they are definitely aware of what they are doing. That is precisely why you will never, ever see a narcissist host a large party with more than a few people who are mutual "friends" of the narcissist. It is very, very difficult to keep track of one's stories/lies in a group where so many people might get together and compare notes.
And, most abuse perpetrated by narcissists is done behind closed doors, whethere it's a spouse, significant other, family member, or "friend." In that manner, if a victim ever has the courage to face the narcissist with the damage that they've inflicted, the narcissist will remain steadfastly calm, rational, and reasonable while the victim will appear to have lost their minds.
Good luck