I wonder how Mr. Campbell feels about this, did they give him a different job? I hope he didn't get screwed over entirely.
My guess is he stepped down willingly. In general, hockey guys pride themselves in doing the "right" thing, and I think he would have volunteered to step down, as it was in the best interest in for league, and it also took pressure off his son.
I also am pretty sure he will just be adjusting his duties, and still has a job, just one not dealing directly with discipline in the league.