Please help..my brother needs help?

hi.. my brother is 16 years old. he started having bad behavior when he turned 15. he started out having depression so he went to a counselor and doctor and got prescribed some anti-depressants. at first we thought they were helping, but my mom and I were wrong. he has ADD, ADHD, AND OCD. he started out by drinking cough syrup, then on to drinking alcohol, then selling my MOMS pain pills. we have a good life, good neighbor hood, and were financially OK. he has about 20 college offerings already at age 16 for his sport ability. just yesterday he called my mom drunk..and he came home drunk and suicidal. he gets angry when he's drunk. saying hes gonna kill himself, no one loves him, and so on. my mom and i cant stand it anymore. we dont know what to do. we want to take him to behavioral health, but he said if we even try, he's gonna come out worse and we'd regret it. i can't trust him anymore and he stresses both my mom and I out. he's done alotta bad things this past year or so.. and it's getting worse. help us please... :(