Freedom1990, Kindeyes, LucyA, mamaplus2kids, and denny57, thank you all for your replies.
I can see there's a lot of wisdom here. It's a lot to take in and process when you aren't used to thinking like this.
Kindeyes, thank you for the book suggestions. I once had that book in the house, "Codependent No More" by Melody Beattie. (I think it belonged to my brother.) At the time, I thought this stuff was all just a bunch of hooie and I got rid of the book. I probably should have hung onto it. My library might have it though.
Mamaplus2kids, thank you for giving me specific examples of things I could say to my brother. That's exactly what I was looking for.
Now I've just got to figure out how long to give him to catch up on his back rent before I have to ask him to leave.