Hi Zen,
This is interesting to read, because I'm in a similar position, but opposite from you-- i'm more of the calm "let's just be positive and not freak out" type, and my brother (different from you) is... basically a bully. he blames and bullies me for everything, yells and screams in public (even in front of my coworkers) and... is just a big cloud of negativity.
I'm having the worst troubles communicating with him...

I've found it would help SHORT TERM if i just ... let him be, let him yell at me, and just sit there with a smile. but now it's turned to "ha! so you have nothing to talk about? YOU are SO SELFISH!!"... stuff like that.
It's so difficult... so so difficult...

I think where i'm at right now... is to either cut him out of my life, or ... i dunno... go to counselling with him TOGETHER.. coz this is not working out. his constant bullying has made me too stressed out... my hair has fallen out from stress, and i've lost a bunch of weight...