Dealing with another drug addict

One of my other brothers was also a drug addict. He spent time in jail several times for selling drugs, stealing, and writing bad check to support his habit. Many times, he tried hitting me up for money to buy drugs. But I always refused. One time, he got so angry and desperate that he threatened to kill me. I didn't see him again until six months later, when he'd show up telling me how much he loved me. I knew this scene would be repeated again and again and I vowed right then and there to do everything in my power to stop my own children from ever getting into drugs.