Breast Cancer and the letter

My sister sent me a picture of herself and my niece at a concert. I noticed her wearing a really awkward hat. When my niece graduated 8th grade, there again was another ugly hat upon my sister s head in the photos. When she went surfing, again another ugly sun hat. My sister has always had a full head of hair. Wild and sometimes untamable. But no more photos of said hair just the hats, so I asked, what's with the hats? To which, rather than get another short text msg, I got a letter. I received a letter, a year after being diagnosed with breast cancer, a year after surgery, chemo, hair loss, weight loss, crying spells, and now remission. You see I've heard the remission news before, only for my kid brother to die 3 months later. The letter was written like a a good bye, or a just in case. I live many miles away bitching and complaining about a shithead husband who yells at me daily, and used to beat me before he knew I could use the law to destroy his career, and take away what he owns, so instead he yells, and belittles me, and treats me like crap, and I tell everyone who will listen. But my sister suffered alone in silence, going on with her life, surfing, teaching, meditating, mothering, and teaching as though nothing were wrong. Why????? I don't understand. How could she be so giving of herself, and be suffering alone? My mom knew all along, no wonder she could care less about my idiotic problems. My sister suffered alone. And then sent us all this letter. What do I do now?