The theory says she's the only one in SH2 who's not able to see monsters or dangers. She only sees Silent Hill as a deserted and abandoned town. That's why she's not worried or scared, that's why she acts like a b*tch with James, because she doesn't know, for example, she's locking him in a room crowded with monsters. Everyone, especially James, seem to care a lot for her, because a lonely child can't wander around a town like that one, but in the end, she never finds herself in danger, like it happens for all the other characters, at least once during the game.