I hate when people take psychological manga with bl themes where it's obvious that the characters aren't supposed to be "shipped" or romanticized in any way and then take that manga as some great romance, like with killing stalking or nii-chan. reply
I think you should talk to your sister and ask her if she feels like she needs help and just don't bring up the diary instead say that you could tell she was feeling more down than usual, and try and convince her to get therapy just to talk to someone. I could tell my little brother was depressed for years but he didn't get serious help until me an...... reply