It might get a little dicey for Ferentz IMO. Your all time leading receiver accusing you of blackballing his career and working against you every minute you were on campus is not a good look, nor is not including your son in the investigation. I know he said the degree of accusations was not the same, but if there are credible accusations I don't see why Brian wouldn't be on leave as well.
I could see this going a couple of ways - DJK didn't flat out say there were racist motives (at least from Kirk), but asked white players to come forward if they also had been treated harshly. If none have any similar experiences, it's going to be hard to hide it all behind Doyle. That's not some scrub who wouldn't have played anyway complaining that he was overlooked, that's one of their best receivers of all time. If non-black players come forward with similar punishments/requirements and other former players come to their defense as well, it will mostly be swept away as "being a little too tough on some snowflakes" and Doyle will be the fall guy.