Your nephew can sue his employer for the amount owed.  The lawsuit can be filed in Small Claims Court.  Your nephew's damages (the amount of compensation he is seeking in his lawsuit against the employer) would be the amount owed plus court costs.  Court costs would include the court filing fee and process server fee.If your nephew is a minor, he won't be able to file the lawsuit himself, but his parent or another adult could be appointed guardian ad litem to file the lawsuit on his behalf.