Hi Patriot,
Welcome to SR! I know the desperation that you are feeling. My son started using pot when he was 13 and moved on to harsher stuff as well. I tried everything to stop the path that I saw ahead of him. He didn't have a cell phone at 13, but if he did...it would have been taken away. Firm rules and boundries are what my husband and I did...and it nearly killed us in the process. Unlike your brother, my son grew up with 2 hard working sober parents...with rules and responsibilities. That didn't stop my son from using. Addiction is a disease and it hits all kinds of families.
I would suggest spending a lot of time with your brother. School is out shortly...have him come stay with you for the weekend. Show him the healthy way to live. Although it may seem that he isn't "getting' it, someday...he will remember that you are somebody who cared and tried to help him and he will reach out for your help. You might want to look into Alateen also since his Dad is an alchoholic. That might be a great support system for him when you can't be there.
I applaud your efforts. Your brother is lucky to have you in his life! I will keep both of you in my thoughts and prayers!
Here_I_Am