She doesn't realize that if it wasn't for her, he also wouldn't necessary strive to where he is today. At the same time, it also shows that she really cares about him, selfless, and is also not arrogant. Both of them are really similar in the regard. I hope that she one day be able to not look down on herself and instead, continue to strive to help her brother in any ways she can. That will also truly makes him happy and in a sense, "give back" what he "gave up" for her.