I broke off all forms of communication with my oldest sister before August last year. She dealt with my transition far worse than anyone I care about including my youngest sister, who's husband wants to stone all the gays. I unblocked her on facebook a month or two ago and have had a few minor interactions with her without incident.
Last night I got an email from her about her son, which included a picture. He's been dangerously underweight and is improving. She also mentioned she misses me, but carefully avoided pronouns or anything gender specific and didn't mention my name (although her email system identified me by my old name).
I decided to respond. I gave her a pretty huge update on my progress since. Since I wasn't on HRT at the time, a hell of a lot has happened so I had no trouble in making it as detailed as I thought was appropriate.
Today I got a response. She still wants me to be her brother, but she does care about me. She didn't try to lash out at me or anything (which is why I had to block her in the first place). I'm hoping this is the start of us moving forward, but it still bothers me that she can't accept me as a sister. I wish she could understand. After all my parents understand now. They certainly didn't at first. None of us knew any trans people (that we knew of anyway) at the time.