Sarah, sorry I have been having a much tinier attitude-based family crisis myself, and your posts have put mine into perspective a bit. I can't believe how cruelly you've been treated, and that truly is an evil thing for them to even think, let alone say out loud to you.... I can't imagine how upsetting it all is, but I know it took great strength to write about it and reach out.
As others have said, you need to get away from such monsters and let them live their own dreadfully empty and mean lives without you. I am so glad you have a friend to go to, and are doing just that. You are one brave and resourceful woman, and it breaks my heart that a decent person like you can be treated like this. You must never ever ever believe that sort of crap - it is low, vile and contemptuous.
This disease sucks our very souls out sometimes and makes the bottom of that deep dark well seem very close... Remember it is always your life and your choice what you do with it. No one can ever take that right away from you, and you must always believe that you are worth so much more even with all the problems this disease has given you, than they are worth with all their physical health. Worth is not measured by what you can do - but by what you choose to do. Not by physical strength, but by mental strength and heart. Not by actions, but by thoughts and dreams, hopes and kindness. Those are things that decent people value and remember.
I wish you all good things. You deserve better, and I believe you will find it away from these people. They might be tied to you by your family tree, but as the saying goes, 'you can choose your friends, you can't choose your family'... Cut the branch of that tree and grow stronger elsewhere.
Good luck and I hope we hear of better times ahead for you very soon. I'll be thinking of you.
Bram