This patient support community is for discussions relating to teen depression, abuse, aggressive behavior, alcohol and drug abuse, anxiety, behavioral issues, fatigue, gastrointestinal problems, grief loss, parent issues, relationship problems, school issues, self-esteem, sexuality, sleep disorders, and step-families.
If you haven't involved your parents yet, now's the time to do it. They need to be aware of what's going on. I think this is probably more than you can handle.
Most kids do have kind of rebel and go a little wild at the first taste of freedom, but you don't want your brother to indanger himself. And if he's failing college, I'm sure your parents aren't pleased if they're paying for that. We gave our son a laptop computer for his high school graduation with one stipulation. He gets to keep it as long as he doesn't flunk out or drop out of college. If he does, the laptop is ours. It makes a good incentive for him to stay in college.
It's good that he has a caring sister. I hope he will appreciate that. Take care.
For your own sake, you must decide what you can do and then accept that you have done all you know how. Keep trying, but do not blame yourself because you are doing all you know how. Sometimes, others do not want our help and all we can do is continue to offer. Your parents should be made aware and you should not carry this burden alone.