Peace officer status does not equate to ability to lawfully carry as a security guard in California. If in security uniform carry must be exposed and licensed.
That said if it's really that sketchy there and if he does fall under LEOSA and has qualified then carrying concealed is something he will have to do his own risk analysis on.
-- Rifle, Pistol, Shotgun
Not a lawyer, just a former LEO proud to have served.
Americans have the right and advantage of being armed - unlike the citizens of other countries whose governments are afraid to trust the people with arms. -- James Madison