If your brother is truly a sociopath, you're merely bringing yourself darn farther by providing warmth & safety for him as well. My sister is a sociopath, and it has taken me a very, very long time to not give everything that I have to help save my sister.
It does kind of help that I truly cannot do it, but, I would have found some sort of way before. Honestly, I would have. I still believed in my family back then. Years later, I realized the truth. I cannot do it anymore. I just can't. Thankfully, my sister realizes that as well, and doesn't lay out full stories for me anymore either. I also never see her, and probably won't for many, many years. Occasionally, I hear how she is via e-mail of some type. The peculiar thing is how it's just like yesterday every time. And what matters to her is HER life ~ plain & simple. She doesn't give a hoot about me whatsoever. never has...
It still hurts. but, that's also the way that it is.