Even if he realises he's done wrong now, he has a vested interest in maintaining his previous thinking.
I've gone from disliking him to feeling sorry for him. I can't imagine what it takes to turn a person into the person he is now. He's also either terrified of what's going to happen to him or he's sociopathic - either way, this is someone's son. They must feel disappointed that this is what he's become.
http://www.truthaboutdeception.com/surveys/2-compulsive-lying.html
Considering what we've learned of him over the last 10 years (see: http://www.gpo.gov/fdsys/pkg/USCOURTS-ksd-2_03-cv-02287/content-detail.html) I'm a little bit curious about Josh Zerlan's childhood and formative years.
Further reading:
http://blog.chron.com/loveandrelationships/2013/01/liars-who-believe-their-lies-are-pathological/
http://drsanity.blogspot.com/2009/05/narcissism-pathological-lying-and.html
http://www.daviddrury.com/2013/01/30/10-ways-lies-grow-stage-6-they-tell-it-to-themselves/
http://www.today.com/health/believe-it-why-partial-truth-feels-worse-total-lie-2D12001361
http://ia802308.us.archive.org/32/items/gov.uscourts.mowd.117531/gov.uscourts.mowd.117531.docket.html
EDIT: Bonus reading: http://www.truthaboutdeception.com/lying-and-deception/confronting-a-partner/compulsive-lying/confront-cl.html