There is no rational reason for Ferguson to remain on the staff, as much as I like the guy. If we transitioning from a successful manager and coaching staff, you could argue that Ferguson could provide some continuity, but he has been part and parcel of regimes that can be regarded as nothing other than absolute failures.
Clearly Brands and Silva were briefed in advance that he is staying on, a bit like fixtures and fittings when you buy a house. I imagine both of them are too consumed with other things to raise any objection, but I can't see him playing a role of any significance. It would surely be better for him to try and cut it in a new environment rather than the comfort blanket that Everton all too easily seem to be willing to provide.
It's no big deal but it doesn't smack of the lean and mean club I'd like to see us become. Nothing against Duncan, but he is a square peg in that dugout.