I agree, sometimes unfortunately relationships change when a friend becomes a boss. You loose the close connections you and probably the other person valued. As a co-worker, he can share personal things with you. As a supervisor, its a finer line.

Maintaining that “close” relationship prior to the promotion AFTER the promotion could subject either or both to allegations of favoritism or other negative comments. Getting input from HR could be helpful on understanding what is protocol at this company (since the writer is the newest member of the company).

Of course, the person could still be hurt that he was not selected for promotion as evidenced by the difficulty in discussing this situation. To get around the difficulties in sitting down with this person, the writer could schedule one-on-one’s with ALL members of the team so the person is not singled out. Sometimes, just giving someone distance to grieve and time to process the hurt is the best gift (but a specific date should be scheduled so the situation doesn’t continue).