Sorry, I'm not sure I understand what is happening. It sounds as if everyone around her is rushing around trying to "help" her while she continues to do her thing.
You've given us no indication that she actually WANTS to stop living the way she is living. She is crying because she might have to go to jail (which might be the best thing for her at this point), and what she is seeing is everyone around her rushing around to save her from having to go.
Alcoholics and addicts change ONLY when they have sufficient INTERNAL reasons to want to quit. I quit drinking because I felt desperate enough inside (despite my life looking "not so bad" on the outside) that I felt I had no other option. Multiple arrests, probation, car accident--none of that seems to have fazed her. What makes you think that bailing her out this time will make a difference?
I know you love your niece, but if love and "help" were enough to get someone sober, we'd all be living happily at home with our sober loved ones.