I'm close friends with an abuser and I don't know whether I should continue to hate myself for not being able to condemn him or if I should accept it.
Sounds like you're struggling with this.
He keeps hurting people around himself.
You should get away from an abuser if you can. It is normal to feel guilt when you see something wrong and fail to act.
He has calculated everything to the point where he doesn't get caught.
There are laws against abuse, and if he's crossing the line, you should report him. I you know the victim, you should try to help the extricate themselves from the situation.