Carlitos kept getting betrayed by the people that were close to him. Lalin, Kleinfield, Pachanga. I think the only person he would trust, was Gail. And that's because she wasn't a part of that life.
Yes, that's right. It's most notable at the end when his brother looks over his dying body and says something like, "Sorry, bro. I gotta look out for myself now, I know you understand." In that world people will turn on you once they feel you're screwed.