For one, it's not necessarily improper for a non-licensed engineer to do "engineering-level work" - the way you become a licensed engineer is to do "engineering-level work", typically under the supervision of a licensed engineer, but some of your experience has to come on your own ("responsible charge"). But more importantly, just doing engineering work isn't the problem, it becomes a problem if you represent yourself as a licensed engineer when your not.
Quite frankly, Cox should file his own complaint with the NC engineering board against Lacy (assuming Lacy is licensed, his name didn't come up in a license search).