Banging my head against a brick wall, repeatedly

a couple weeks ago, my old friend Ri got arrested
she asked me to sponsor her, spent a weekend at our house, called me a million times a day, leaned on me HEAVILY, to the point were it was really disrupting my life
I helped her as much as I could, thought she might finally, after over 6 years of trying, get sober
I talked to her about 4 times yesterday, the last time was at 10 pm
she was fine, she'd been to a meeting, had a productive talk with her daughter's aunt about custody (her daughter's dad had custody but died suddenly a couple months ago)

so, I get a message on facebook this morning from her older daughter, Ri's gone missing
her daughter woke up this morning and found her cell phone & work bag but no mom
I thought she was dead
turns out she just got arrested, again
I'm not sure what for, but I'm sure it's alcohol related
I haven't heard from her
I don't know what to do. Obviously I can't sponsor her anymore, I'm not helping
I should have said no this time (last time she called me drunk to tell me she hated me in the middle of the night)
I can't believe this but I think I need Alanon over this shit
AA just doesn't work if you won't be honest, open minded & willing
she's none of the above I guess
it breaks my heart, because I really like her as a person, as a friend
and I can't save her