I just wanted to tell you that you are not alone. I have a 12 year old daughter and almost 6 year old son.
They are fighting CONSTANTLY! About everything!
We are so sick and tired if it. It makes us tired (literally), to hear them bickering and fighting all the time. We had a "family meeting" the other night. We decided to try to lay out family ground rules. I will be getting this posted up very soon. We have planned on trying to involve the kids more with activites. Which is not going to be easy as both me and dad work full time and also some weekends. So they are home alone after school for about an hour and a half.
We can up with a dinner menu for the week. Everyone gets one night to pick what they want. Then we planned movie night and a game night. I am not sure if this will work or not, but I figure to give it a shot.
As for family counseling, as someone suggested, we have been in counseling for years! Nothing has changed much. Advice that was given to us was: don't get involved with the arguements, don't become the mediator, let them work it out. I can't stand to listen to it! This did not work for me. Then it was to talk to them about what they could have done differantly. This only worked if we stepped in, thus, back to rule #1. And after talking to them, it seemed like nothing "stuck". They were back at it again. I have tried taking things away, sending them to time out, to their own rooms, trying again, and still nothing works!
You would think that a 12 year old could be more helpful and understanding, but no. She has to have her way, then lies to us about everything. I am as stuck as you are.
I hope one of us can find a solution to this problem. I will send you an email if I find something that works, and I would hope you do the same for me.
I would be open to chatting online about this with you, so we could bounce ideas back and forth and to talk to someone who really understands.
-M.