I am not a lawyer, but watch a lot of tv.
He was faking identities and committing bigamy, oh and abandoning a child and not paying child support and who knows what insurance claims were made. The Browns (sister wives) moved states to escape an investigation into bigamy. He could have been sent to jail, and he's immortal so if the charges stack up he's serving out every year.
He's lucky he only had to pay off his husband/wives. Plus Nikki and the lawyer (can't remember her name) were obviously disgusted/weirded out by what he was doing. They didn't HAVE to represent him, but if he went anywhere else he might face legal problems instead of a civil case that could be easily solved in a day outside court. His ex's got everything they wanted, but he got off easy.