Stickin' it to me from the grave
Yesterday I got home from a 9 hour day at work to find the codicil and will that I asked my grandma's estate lawyer to send me.  The week before, his assistant had sent a copy of the 2nd page of the codicil, which mentioned the 1.5% of the estate that my brother and I were to recieve after all debts, taxes, etc. had been paid.  My dad and sister were entirely left out.
Upon reading the will and full codicil, I turns out that Grandma wrote the will on June 9, 2003.  The codicil was written on Oct. 20, 2003.  The will allocated 3% to my bro, 3% to my sis, and 4% to me.
I called my dad to ask if there were any significant family things between June and October 2003; he couldn't think of any.  I thought of my neice, Shayna's birth.  But that didn't seem like something to write us out for.
I then called my sister.  She thinks it was changed because we didn't come to Grandpa's headstone unveiling.  
Adam, my bro, didn't pick up the phone; I left him a message. 
I'm thinking about calling my aunts to ask for an explanation.  I know it's inviting trouble and more heartache, but I want to know why Grandma changed her mind in such a short period of time.  Ugh.