So sad, my sister has stage 3 breast cancer?

My sister has just been diagnosed with breast cancer, stage 3, T3 no mets. Hers is a rare occult type, no identifiable tumor in the breast but 3 lymph nodes removed, all cancerous, over 10cm mass. She has lost the plot. She is saying she won't have any treatment because what's the point, she's going to die anyway. She lives overseas, far from me. I want to go to her, but we've never been close I guess, and she says "don't come, I don't want you here". I want to go and drag her if necessary to treatment. I said I'll shave off all my hair too so she doesn't feel so bad. What should I do? Respect her right to not have treatment, listen to her saying "no, I don't want you here" or go anyway and try and make her see reason (if I can). I think even if she had a 1% chance of living 5 years or more, she should have everything and do everything she can. She has a 9 year old and a 3 year old. Her husband is useless, he's depressed and won't get out of bed. I want to kick him up the ar**. Maybe that's why she doesn't want me over. Her marriage was pretty much stuffed before this, but he won't let her come home (Australia) with the kids. They have to stay in France. What a mess, what an awful situation. I feel so powerless. I feel like "kidnapping" her and the kids and bringing them home so I can look after them all. I'd go to jail if I had to, I'd do that for the sake of her and her kids even though we aren't close. Sigh.