Kim, I am crying here reading your story. I am so sorry your sister has lost her beautiful babies, and that you have lost a little niece and a nephew. You are a very loving, strong and compasionate sister hun, I would be so proud if I had a sister like you. Listening to you telling your story, I just can't stop crying. I wish I had this sort of support from my mum. Unfortunately, I don't have a sister, only a brother who just doesn't get it and a mother who doesn't understand.
Keep the lines of communication open with your sister if you can, she does need you hun. I bet she thinks the world of you and loves you very much.