evil brother

isn't it always those close to us that know just how to hurt us the most...and yet I hear myself sounding like a cracked record.
My bother is the bain of my life,he manages to break my spirit with the minimum of words or actions,yet he has mastered how to get into my mind,or maybe it should be I allow him.
He is cold as ice most times,why does this matter....?
I help raise him from 4 years old when our mum died and I was 18 yet 40 years later you would think I had commited the worse crime towards him.
I don't want undying devotion,but just a little feeling and compassion would help so much right now.
Most times our paths never have to cross,which th eonly way I can handle it,but then he comes back with advengance.
On minute he id as nice as pie,lulling me iunto a false sense of security,then wham he flips to Mr nasty....his Jekyll and Hyde personality is a contant featue.
There was a time when he nearly caused me to take my life,when my dad died,he blames me for this by the way,although my dad had a heart attack on hiss last day at work.
I guess I need to find a way of building a barrier around myself for protection as its happened too much for the last time.
Not sure how to handle this,and find myself constantly crying....