sue, i don't know why you bother writing these long winded descriptions of your life, you say you're asking for advice, but you're actually asking people to agree whole-heartedly with you, and say 'poor you'. we all have moments in our lives that are traumatic, they may go on for moments, or years, but you have to move on in your life, and not blame other people for the negativity that you feel.
it is not your brother's fault that you married a ****er. your brother had his own life and marriage to nurture, like you had yours, it's not his fault that you had grand expectations of him to fix YOUR life.
i know i sound harsh, but for gods sake, move on.