I have a sister 4 years older. For many years we were friendly/distant. We saw each other on holidays, but never spoke on the phone.
I was visiting her last spring, and, while walking her dog, she asked me (firmly) what was wrong. It all spilled out. A lifetime of GD described in a run-on sentence. At that very second, I knew I had to transition, and that enough was enough.
Over the course of Therapy, Doctor's appts, and lots of crying and WTF moments, my sister became my rock. She held my hand literally or virtually as I began this strange journey. She treats me like the sister she never had. We have become best, inseperable friends, and see, text, or email each other every day.
My sister has let herself erase from memory the male persona I had. I am only female to her, and always was, and that is how our relationship works.
Big sister, mentor, Yoda, and advisor. These are things my sister is to me. The years we were distant are forgotten.