I know it seems bad, but i think its her way of dealing with things. She must be really hurt and she is trying to act as though she doesnt care, when really deep down she does. I bet if someone outside the family circle had a one on one chat with her, she would open up. Try not to expect too much from her. Just because her partner has cancer, it doesnt mean he cant do anything. I know lots of people with cancer, and their life doesnt change that much. Just get someone to have a word with her and get her to talk about how its affecting her life...