WHEN IS IT ENOUGH...

My new dilema this week is with my 9 year old SS, he and his brother were fighting over a video game the other day while I was at the store, dad was playing his own video game with headset on, tuning his children out...UGH!!!
Some how when I walk in I am pulled right into the middle of this fight...the 9 year old played something else when it wa his turn to play and now it was the oldest's turn to play...I tried to explain it to the youngest one who clearly did not want to hear anything I had to say about the matter. This by the way is his reaction to anything that I try to say to him lately...anyways it escalated and the 9 year old SS told me that I MADE HIS LIFE MISERABLE this is not the first time he has been rude and disrespectful to me, actually it is a regular daily thing, he treats me and his brother rudely and has the attitude that he is always right and we are always wrong...and then when dad comes home...he acts like a phoney...he treats us nicely and pretends nothing was ever said or happened. So as of late I have really been trying to hold the SS9 accountable for his words and actions. I do this because I think that if this behaviour is allowed to continue now that it will only get worse as he moves into his teenage years.
Now I was so hurt and upset that I probably should have just walked away but instead I told the SS9 that the only reason I made his life miserable was because I hold him accountable and that he wants to do what he wants and when it does not work the way he wants he blames everyone else, and I left the house.
Also dad was told by the oldest as to what had ocurred...but the SS9 was not grounded, he was not made to apolize, he did not lose any vidoe game privleages...nothing...now what am I to think about that?
It makes me feel like its was ok in his dad's eyes and dad has not broached the subject at all and if that is the case maybe it is time to move on. Maybe it is anyhow...when someone tells you that you make their life miserable...maybe it is time to move on?
Thoughts?????