Re: anyone
I'm so sorry for your loss! And, isn't it just awful how badly people behave when there's been a sudden (or, anticipated) loss of a family member? Holy moley, but that's when you can see the stripes on the cat, right? Sheeeeesh.
For me, it was "easy" to move on as per the divorce. After a couple of years, I went to see a psychotherapist that specialized in domestic violence and abuse. I learned so very much about how I had allowed myself to be victimized, even by my adult offspring. I knew that I wasn't insane, because I could clearly remember days, verbatim quotes, circumstances, and the consequences/punishments that followed any altercation with my ex. I was finally able to walk away from the humiliation of having been played like a fiddle, and begin healing the damage that I had sustained.
With regard to your brother's effects, just keep those things that are meaningful to you. If your sister is so hot to search for his Will, let her. And, be sure to mention that you will no longer discuss any issues (OF ANY NATURE) via emails, written letters, or telephone conversations. Any "family" discussions will take place with all parties involved, at the same time, in a neutral place like Starbuck's or some other public location. Try writing down dates, times, quotes, and your own responses, even if your responses don't make you look that great, either. At least, you will have noted the patterns. You could also try recording conversations using a digital recording device. In that way, her own voice will be recorded and such evidence cannot be refuted.
In addition, I would gently suggest that you consider seeking out a family counselor/therapist that specializes in domestic violence and abuse. Although you aren't being physically beaten by your sister, you are certainly suffering emotional abuse!
At any rate, hang in there and just be assured that you aren't the first person (nor, the last) who has a sibling that is a narcissist. : )