It's bad enough that alcohol is a depressant, but mixing it with meds can really mess people up. Maybe don't tell her it will kill (because of the suicide risk) but warn her it can mess up her liver and it will be painful.
If she is having problems remembering to take her meds, maybe find her a pill case with the days of the week on it. I have one like this:

and it has done me wonders to make sure I take my pills because I can see if I have taken them or not. If you just take them straight from the bottle, you can forget if you took your pills that day or not, and that can lead to missed doses or overdoses.
Try and be there as much as you can (as much time, and more importantly, how much of your energy you can give) to let her know that you care about her. But don't let her pull you into her world. I know for me, I like to talk when I'm down, it helps me process. Other people like to be alone. It just depends on what works for her. But don't let it consume you. Don't spend so much time helping her that you neglect yourself. Also, if you are being emotionally supportive of her, make sure you have someone who you can support you. If you just give and give and give, you will have nothing left, so make sure you have someone who you can get care from (it works best if it's a mutual relationship, but I'm pretty sure she can't give at this point). I can't stress it enough - make sure you take care of yourself as well. I had a friend who would just take, take, take and I had nobody to help me, so it made me crash as well.
When you start going down emotionally, that's when you should start stepping back. If you are going down fast, tell her that you need to take care of yourself. It might be selfish, but it's better to have one of you doing okay than both of you doing crappy.
*edited to fix picture*