Wow! It sounds like you really have your hands full.  My son who is now 14 was diagnosed ADHD at 8 and we did not start meds till he was 13. 5 very long years!  He did unfortunately jump down a flight of stairs and earn a compound fracture to his ankel that needed to be surgically set....He regularly climbs the trees and is an aggressive bike rider.  I also have a daughter who is 2 years younger and has had to learn how to co-exist with him.  The good news is that it will get better!!!!  As they get older my son has developed more healthy/safe outlets and his sister has a great understanding and tolerance.

I had many discussions with my daughter explaining what was going on with her bro and suggesting ways to protect herself and still enjoy him.  They have a wonderful relationship and have learned how to play together and both get something out of it.  On the weekends when they were younger my husband and I would split the kids so they each got some one on one attention and did not have to deal with each other.  If leaving your son with a sitter is not an option then let a sitter take your other kids to the movies or the park so they get some time away from the fray.  This will also give you some one on one time to work on relating to your son.  When Jake was younger the most powerful thing I could say to him was I know you are frustrated, I understand that you are finding it difficult to make the right choice, I hear you! Now, I need you to hear me, I need to work with you and make some deals here.  When he felt validated he was much more receptive.  Good luck and hang in there!!  I hope this is helpful!!!