This is the awesomeness of German. Like another phrase in this lesson (Occupation Lesson 4) is Mitarbeiter, or "with worker" for co-worker. Also "Arbeitgeber" or "work giver" for employer. I don't think any language does this as well as German.
Yes, a close friend or family member would make "du" acceptable. You wouldn't go up to a mayor you aren't related to or have a good friendship with and use "du". That is way too familiar for someone with that position.