My friend is a man who is a great father and husband. He has been married for almost 2 years, but overall has been in a relationship with her for 10 years. He for the longest has wanted to get out the relationship, but his son is the main reason he stays. Not to stereotype the woman he wants to divorce, but she is a very troubled and abusive spouse. She is physically violent and emotionally abusive towards him. Bite marks, black eyes, bruised arms. She is simply turning into someone he cannot fathom to live with for long.

However, they have a son. She has told them even before they married (which she threatened the he marry her or he will never see his son) that if they separate that she will manipulate the court system that she works in to have her son kept from him. She has her whole family involved. She purposely send texts to her for her to save that only gives a glimpse to a particular situation that makes him look like he is abusive to use as future evidence. Its just a very unfortunate situation.

How can my friend be able to get a divorce and ensure that he will at least have joint custody of their child? (Besides the obvious of saving money to hire a lawyer and potentially just be fucked by the system - that's the only advice he has received).