The connection between strong negative emotions and the compulsion to action is usually our downfall. (So it is with food, drugs, alcohol... any addiction)
Some suggestions for alternative actions? (Some worked for me, some didn't. I tried them all until I found what gave me the ability to think through the emotion to a constructive rather than destructive action)
Get a glass of ice cubes. Crunch them in your mouth.
Compel yourself to a physical action (walk around the block, go up and down the stairs four or five times, play Wii, Xbox, etc. Something you can do right now to wear off the adrenalin of the emotional hijack)
Speak up - even just a little. Give yourself a voice. Stuffing what you think about the circumstances results in an emotional void needing to be filled.
Call someone you trust and set the timer to vent for five minutes, then talk through what action you need to take to be positive.
Journal - stream of consciousness - no self-censoring. Fill three pages with the thoughts in your mind. It won't be pretty, it won't be nice English, but it will get those destructive, habitual thoughts out of your head and into tangible form. After three pages, put the journal away and make a date with yourself to read it later. Later, when you do read it, make some concrete decisions about how you want to think about (______________) behaviour. (i.e., your brother's) Even if you can't talk to him, you can write him a short note taking personal responsibility for your response to his words/actions. Something like, "I was very (emotion) when you (action) and I need/choose/ask you to stop/change. If you don't, I will need to limit our contact for my sake. I choose not to be a part of that kind of encounter again." Or something similar. You may not be able to say it to your brother, but you can use the opportunity to practice self-advocacy.
Lastly, use positive self-talk. When you're not in an emotional crisis, learn some things you can tell yourself when you are. "I am not compelled to action because I am feeling (emotion)." And other phrases that you learn when not under stress. Using them does make a difference. I promise.
Keep at it. All this stuff is so much easier to say than to do. But you already know that. Sometimes, just having extra tools/ideas can make all the difference in the world, one stressful situation at a time.
CE