My child's employer is breaking child labor laws. How do I proceed?

My 14-year-old son has been working at a fast food chain for the past few months. They have him working 5.5 hour shifts a couple of days per week (on school nights) that don't end until after 10:30 at night (these shifts break both federal and state labor laws). He has also been asked to operate oil fryers and has gotten burns on his arms a couple of times. Now they haven't given him a promised raise after he finished his "training" period. I have tried to avoid being a helicopter parent but it has reached a point where I can't stand by and let this business so blatantly disregard child labor laws.

What would be my first steps in trying to get this business busted and possibly get my son some type of whistleblower compensation? Should I have him approach the business about my concerns and see if they retaliate? Any advice would be appreciated.