He didn’t “practice engineering” since he did not engineer anything.
Did the Chicago Tribune “practice engineering”?
http://www.chicagotribune.com/ct-red-light-camera-safety-met-20141219-story.html
Sue the Board.
He also wasn’t paid for his work, so by definition no professional services were rendered.
He would have had a much stronger case if he had just submitted his document as a lay person and never identified himself as an engineer. State licensing boards deal with this all the time, and I think they’re on pretty solid legal ground.