I'm so sorry. It is so sad. You have reason to be proud of how you are handling it.
My nephew is 18yo. He does a lot of drinking and getting high, like a lot of his friends, but his behavior is different. His attitude is different. It has a hold on him. He isn't doing anything else. It is so frightening to see and facebook puts it all out there. I want to make time stand still for my kids. I'm not sure how I could go through something like that with one of them.