California Legal Code 96(k) states that: The Labor Commissioner and his or her deputies and
representatives authorized by him or her in writing shall, upon the
filing of a claim therefor by an employee, or an employee
representative authorized in writing by an employee, with the Labor
Commissioner, take assignments of:
...
(k) Claims for loss of wages as the result of demotion,
suspension, or discharge from employment for lawful conduct occurring
during nonworking hours away from the employer's premises.
You're citing a procedural detail that I don't think really supports the claim that his termination was unlawful.
All that section says is that if the guy files a claim with the labor commissioner for wrongful discharge, then the commissioner can "take assignment" of his claim, meaning they can sue the company in his name. It doesn't really say anything about whether his firing was OK or not.
http://www.leginfo.ca.gov/cgi-bin/displaycode?section=lab...