has she actually tried killing herself, or is it just self mutilation...the two can be related but self mutilation does not necessarily mean a person is suicidal, just ill equipped to deal with overwhelming emotions like anger, hurt, and even love. If a person wants to die, they will. If a "suicide" is orchestrated for discovery, than the person is trying to get attention for something.

why does your sister feel that the only way she can be heard is with a razor to her flesh? Often times it's when people feel powerless...that they take extreme measures.