How can my ex husband and I deal with our teenage daughter's rebellious behavior?

My ex husband and i have been divorce for 2 years we ave 2 wonderful kids a 13 year old son with autism and a 15 year old daughter. These past two years have been hell for me and my ex we both have joint custody and right now my daugther is currently in therapy. My daughter has started dated this boy he's a senior in high school i think hes a bad influence on her my ex and i forbid her from seeing him but that didn't work. She has gotten really rebellious her behavior change after her best friend died in a car accident they were really close like sisters. She started drinking, partying and failing school i caught her drinking a bottle of wine i grounded her for a month but that didn't work out so i let her live with her father for awhile. One day she unexpectedly came to my house sobbing telling me her father touched her my ex denies it he was arrested and charged with child abuse i overheard talking to her friends joking and lauging on how she lied to me about how her dad touched her and that i was so stupid!!!! I git mad and got er to admit what she did she told me the truth she apologized to her father and the charges was dropped but that wasn't enough she caused so much heartache in this family its not even funny. I am so burnt out right now i don't know what to do with her i have failed as a mother i provide so much for my kids i love them very much i will do anythhing for them between her behavior and my son's autism my ex and i are out of options i know what she is going through been there done that but what can my ex and i do as her parents to snapped her out of it?