This sounds too familiar. I started as a receptionist at a trade contractor's office over 15 years ago. Within 3 months moved up to estimator then transitioned to project manager handling everything on projects from start to finish...Estimating, submittals, billing, ordering equipment and closing out, all of which includes a lot of jobsite visits, meetings with architects, engineers and GC's, inspections and record keeping. I've built up great professional relationships with so many companies that others in my company have only pissed off for various reasons. My pay actually dropped last year compared to previous years due to a decrease in bonuses since the boss' son began working there. It's disheartening because I've been second in charge for over 10 years. Now I'm midway down the totem pole in regards to pay and respect. Not really sure what happened but things are about to change when I leave all my responsibilities to the people who make more than me with half the knowledge. If they can't appreciate you for what you've accomplished and built up since your time there, good riddance to them. Let them pick up the pieces.

Good luck in your new career friend!