EVERYONE PLEASE ANSWER!!!! its long but please read, i need these answers! addiction?

so i been trying to get as many asnwers as possible on this question. i posted yesterday about this 16 year old girl who drinks, does pills, smokes weed, in the past done bath salts, crack, coke, e pills, computer duster, robo trip, unisom sleeping pill trip and a few other things, this started when she was in 8th grade. she been through alot in her life, more then you could probably imagine so i feel as though she hides her pain with these things. her moms an alcoholic and tried killing her when she was 8 years old, she forgave her mother but being she loves the booze to much she isnt in her daughters life, she reaches out all the time for her mothers love but always gets let down, her father step up and been taking care of her but his health is getting worse everyday and she has said it hurts to watch her bestfriend slowly go right in front of her eyes,she is pretty, popular, funny, outgoing but has this problem of not wanting to stop partying. she is known for being a party girl, always the life of it! not to many people know about what she does, besides drinking and weed, and some pills, she keeps most of it a secret but were really close so she tells me alot! shes always drinking, she used to get good grades and play sports but now shes in 10th grade, completely failed this year, fights, gets in trouble, and just doesnt care! she breaksdown all the time in tears expressing how she never thought her life would be like this at 16 but it is and shes confused. now, she swears on everything she can stop but doesnt want to right now because shes just living her life as a teen and having fun, many of her loved ones dont see it like this. im truly concerned about her and dont know how to help. do you think this is a problem or simple growing up and learning from dumb choices???? all she ever wants to do is get messed up, like all the time. i mean she can go a few days without it, not by choice but because of no money or w.e but she told me she hates it and as soon as she has the chance to get something to mess her up, shes on it, its so sad! she got caught in a vehicle, underage drinking at 14, she went to drug and clcohol classes but obvioulsy it didnt do much, a few weeks ago her mom had bought her a bottle and she went to a friends 21st bday party then the next day her parents set her up with the cops when they went to pick her up the next morning, well it was early and she didnt sleep yet so she was still drunk, she was angry on how her mother got her father involved plus the cops, she was flipping, screaming, going off so they took her to the hopsital and 302 her but she changed it to a 201 so it wouldnt be on her record, she told the counselor everything and they decided she needed help and tried sending her to a facility but she signed herself out and continues to live this life. she said she doesnt want to stop because she loves her life now, she has so many friends, and everybody knows and loves to be around her, but i still feel as though she isnt happy so she drinks. she didnt come to school today so i called her and she said it was because the school had called yesterday telling her father that shes dresses to inappropriate for school, honestly i think she has a beautiful style! she doesnt show off anything at all, she is a little bit insecure so she would rather be covered up then flaunting but she dresses fancy, like nice shirts, all the time but the school has an issue with it so she said she gives up trying to please people and what they want out of her but then she also said omg cant wait for tomorrow, the percocets come then im going out and getting a bottle and having fun, i didnt know what to say because either way my words will not stop her, ive tried before. higher authority have been involved, she has children and youth services in her life because her sister was on this same path at 13 then ran away and now is in a foster home and doing great, shes 17 now and going to college in the summer, my friend just wasnt as lucky as her sister to be able to get away from this life. she also became sexual active but not just with one guy, very promiscuous! she slowed down though because i know that hurt her as well being used and just tossed away. she wanted her sweet 16 to be awesome and fun but she doesnt even remember it because she was so drunk, guys took advantage of her at her party, she had hundreds of people there, it was huge, everyone had fun but she blacked out and dont remember, she cried for days because she was scared to show her face, she didnt come to school for a while, eventually noone cared about that anymore so neither did she! she tried going to church and change her ways but again one night she thought she could go out have a lil fun then stop but nope she stopped going to church and replaces that time with drugs or alcohol! idk, i love her and im just worried this is a developing problem?? what do you think about this situation?