Wedge, that is awful. I feel for you.
I just had a death in my own family. The pain is incredible for all involved. Would it be okay if I told you what I know about anorexia? (other than the obvious fact that your sister isn't eating). We have five basic needs: survival, love and belonging, power, freedom, and fun. What an anorexic does is gives up survival for power. I know that sounds like a shitty thing to say, but, bear with me, Wedge and see if what I am saying has the ring of truth. Here is what happens: We all have picture ourselves in our 'ideal' or 'quality world'. Anorexics put a picture of themselves in their quality worlds as being thinner than WHATEVER image they see in the mirror. If these women hold rigidly to this unsatisfiable , changing image, they will starve themselves to death. This is true, regardless of how much they are cared for, they are not satisfied. What they will tell you is, I want to be thin. The truthis they want to control those around them. Since we all see the world not as it is, but as we WANT to see it, the anorexic might INTERPRET care as CONTROL. Some where along the way they discover that starving themselves gives them an unexpected feeling of POWER over the people they believe are not treating them the way they want to be treated. When a powerless young woman or girl suddenly has control over her entire family, it feels so good that she can't start eating. She becomes addicted to endorphins and fails to feel the pain of hunger. If she ate, she would lose all this power and the pleasure that goes with it. Anorexia is a graphic example of the strength of the 'quality world'. The wrong pictures can ruin lives. Wedge, it's a powerful thing. How hard would it be for someone to try to tell you the things you visualize as being perfect are all screwed up? Real hard, I'd bet. The thing is, no loved one, parent or sibling can or should support that crazy picture your sister has in her head.
My advice: Tell her the truth: I love you, I care what happens to you, but I can't support all you want to do. The treatment of anorexia is a tough one even if you know what is going on. Just love her and explain what is going on in a supportive way, Wedge. Just chose actions that bring you closer together.
Sigmund Roid