Most Helpful Guys
First up from a first hand perspective its not your fault. But as family if there's anything shy of dragging yourself under with her try to help. Foremost tho try to encourage her to seek help herself. Remember you can show a horse to water but its up to them to drink. I've been in this situation and im barely getting out of it due to a drinking problem but you can't blame yourself for her mistakes. You can however help her find the strength to fight for her future tho.
Time heals a lot of things but alone? Not possible. Your answer lies in the questions itself. Try to talk to her, try to enjoy with her and take our out, teach her what you've learnt in life and make her feel like she's a responsible person and not a looser. When her brain will be busy with things she'll think less and try to do things. Start a new life again. It would be better if you could explain the reason behind all this.