You can file claims with the department of labor for unpaid bonuses earned while working at a company.

Anyhow he was still working at the company at the time he should have been paid so the money was owed to him and he could have filed (for likely at least the interest on the bonus if not wages up until it was paid).

"Unpaid wages, including commissions and bonuses."

http://www.dir.ca.gov/dlse/HowToFileWageClaim.htm

Either way it's a moot point now.