Bipolar/Adhd Brother- Walking time bomb...?

My brother is only 13 and at an early age he was diagnosed as Bipolar and Adhd, he takes medicine to control him but it doesn't seem to work and I know that my parents have tried it all. I don't know what to do, my patientence with him is wearing thin, he's really abusive physically with my younger brother who's only 9. He'll throw tantrums, kick things, throw things and even starts hitting people. When my parents or me tell him something or try and reason with him things always end up out of hand, there are times when he'll try and runaway or kill himself. We've tried everything.
I need some sort of advice, something to tell him that we may not be on the same page, but I'm willing to be here for him and help him through things. What can I do?

It's good that you understand & want to be there for him despite the things he does.
Would your parents be willing to talk to a doctor about his diet? I've seen research (been a while, don't remember when or where) about caffeine, sugar, & aspartame adding to the mood swings in these disorders.
It would be worth a try to talk to a doctor about it.

well im not really sure what to say but why don't you secretly video tape him while he is in that state of mind. first try to explain that the way he is and how he acts is wrong. if he doesn't believe you than show him the video and ask him if that is the way he wants to be like in the future.

I have a brother who did exactly the same things. My brother also had a thing for stripping naked in public and running around. He also drew out weapons occasionally.

My way was to physically beat him whenever he did this. I know everyone says violence isn't the answer but when you're dealing with people who refuse to control themselves sometimes will with they are afraid enough. The running away is common, they do it all the time, the best thing is not to chase them but let them return on their own. My brother didn't show much improvement until he hit puberty and now things are better though he's a punk and disobedient.

Basically when he acts like a jerk and thinks its ok to attack others, let him know what it feels like to be hit. Remember to encourage him whenever he acts correctly though.

see if there is a chldren's psychiatric in your area. I know they are very hard to find. If you have a local mental heealth center they should have at least 1 child therapist that should be able to see him for talk therapy. Some times kids will open up easier to an outside individual. If none of these are availiable get him to another type of dr. he sounds like if he is on meds he needs a check-up or if not on meds he needs to be meicated. Now with ADHD and bipolar the commonly used medications such as ritilin will not work for bipolar so he should be on something like Trileptal or Lamicatal. Trileptal works great with both of my kids bippolar