First, for God’s sake, seek the input of someone more qualified than a creepy, transgressive writer on Tumblr. You’ve got a major problem that will require a carefully considered solution, hopefully crafted by someone experienced in navigating the complexities of a family in crisis.
But before you go spreading her business far and wide, you need to talk to her. You need to find out if she sees it the way you do, or if your help will be considered intrusive and unwelcome. A well-intentioned outsider can accidentally trigger an abusive outburst that makes things much worse for her; proceed carefully, focus on supporting her rather than saving her, and encourage rather than push her.
Do your best, and don’t expect to change her world. Only she can do that.