To be frank, I don't think there's much you can do except keep your fingers crossed and let the chips fall where they may. J may end up snapping out of this when she's 18 and has to do things on her own, her dad may step in and do something, or she just may have to figure it out on her own.
It doesn't sound like you're ready to make any drastic moves like having J come live with you or becoming guardians in some way.
IME, you should try to maintain contact and be a sister and a role model as best you can. I loved your post about your weekend with them this summer. Try to maintain that positive experience and not to be too judgey, just try and be there for them both. I know you want to save J from making mistakes, but that isn't your role. And unless she asks you for help, I'd try to just take an interest in her life and your other sister and let them come to you for advice.
I agree with drloretta. These kids really have the odds stacked against them. I would just try to have some kind of relationship with them (maybe via facebook or text). Increase your contact as much as you can. Try to be a voice of positivity. J's done all this terrible stuff, but can you really blame her? So much turmoil in her young life lead her to this. There is another way to go and I would just stay in contact with her to let her know that. Be a friend and sister.
Another drloretta team member. Short of moving her/them in with you, I don't think there's much you can do except try to stay in contact and be a positive influence via technology. You certainly can't do anything to change your mother and that's what would have the most impact, unfortunately.
I think the key to having any kind of relationship/pull with teenagers is to not approach them like you're judging or trying to fix things. Just being there to listen and not act like you know better will be different than about 90% of the adults in their lives.
If it were me, I would probably focus on just attempting to be a big sister at this point. It doesn't sound like you have much of a history with them, so start there, and if they need help or if the opportunity presents itself, then you can offer guidance or assistance. One of my favorite things about my relationship with my big sister is that she knows how crazy my mom is and we can relate to each other about that. So it seems like you have that going right off the bat.
To be frank, I don't think there's much you can do except keep your fingers crossed and let the chips fall where they may. J may end up snapping out of this when she's 18 and has to do things on her own, her dad may step in and do something, or she just may have to figure it out on her own.
It doesn't sound like you're ready to make any drastic moves like having J come live with you or becoming guardians in some way.
I appreciate the frank opinion, and that's pretty much what I've come up with.
Something I learned early on as a teacher is that I can't control what the kids do. I can't stop them from making bad choices. All I can do is model good behavior and hope it makes a positive influence. Just like mrshandy said, I can't blame them.
Another option is to have them out for a long weekend here or there on school breaks, etc. That may give you an opportunity to model some good behavior and get them away from irresponsible parents. But that's the most I would do.
Having a somewhat similar life with a crazy mom drinking and running around with men, and only having a distant older sister to model and look up to (she is amazing btw and we are super close now). I will say do whatever you can to maintain communication with them. Send them care packages and letters/photos/whatever to let them know you are there ready to listen and help. She probably feels very alone and even if she doesn't reach out to you now there may come a day when she will. When it comes time for says, college apps, etc. call and remind your mom, etc do Skype to talk over applications and help read over their essays (at least the one who is more on track for this). They need to know someone cares and is invested.
As much as you want to avoid the drama it sounds like your sisters really need you as a constant in their life and someone they can reach out to even if you are far apart. You sound like a good sister and they are lucky to have you even if they don't keep up right now.