My parents have a year to live at best. Their trust has the money divided equally between their four sons. My youngest brother is a parasite of the worst kind, undeserving of a nickel. My oldest brother is the executor and I am the successor trustee. I would like to take steps to eliminate my youngest brother entirely. Is it too late for such drastic measures?
That might be true that he's not deserving. But it could equally be true that you want to cut him out to increase your share. And I suspect that's the case.
Bottom line is that it's not your money, it's not your trust. And it's not your decision. I think your question and what you're attempting to do is despicable. It paints you in a worse light than you're trying to paint your brother in.
If you do try to leave him out, can you document money that he was given during your parents' life, that means that he already got his share? I'm sure your lawyer will know all about this. Also consider making a videotape of your parents to establish that they did this out of their own free will.
Why can't we all just get along? (Maybe because of people like your brother.)