My friends BF rules with an iron fist... 10 points to best answer!?

I have a close friend that I think needs help. She is with this guy. They have been together for 6 years, and they have a 2 yr old son. Her boyfriend is a dictator. He tells her that he makes the money so she should do as she's told... ex, cook, clean, have , be quiet, and do as she is told. He is also cruel to their son, his policy is punish first and ask questions later. He is a truck driver so he only sees them on weekends, but he just sits there and plays his games. He is a addict and a pervert to everyone. Now the problem is that my friend says that he recently started to act like this ( the past 7 months). I wasn't around, we just recently got back in touch. Also he told her he is so mean to her so she won't leave him, and if she ever did he would get even. He loves her as crazy as it sounds, and when they are good, they are great. Only the bad outweighs the good. What should I do for my friend, or what can I tell her?