Others here work as actual accountants and auditors and can add more. I am going off my experience working in a Big Four accounting firm, albeit in an IT capacity and 20+ years ago. One of my projects was a workflow application to track the stations of the cross, as it were, of the firm withdrawing from an audit, to protect the firm, by creating an unassailable paper trail of the client's misfeasance and the steps taken by the firm to document same, warn of same, and eventually flee from the burning building.
That the auditor is walking away from a big and (presumably) prestigious account is very, very, very bad. They want to leave no doubt that they have not participated in or enabled some kind of wrongful behavior - negligent at best, usually deliberately criminal or fraudulent.
I believe, and I know you do too, that Morshri - whose purported 1.7B wealth is not that much, for owning a club with 200M annual turnover and a 500M stadium under construction - has been a front for Usmanov who's probably worth 10-20 times that. With Usmanov's defenestration Moshiri is caught with his pants down.
My guess is that the club gets sold at pennies on the pound in a distressed-asset sale to an American, Saudi, or Emirati group. With the new stadium it's an attractive proposition for a buyer if there is a heavy discount for buying a collection of cooked books, as long as we don't get sent down.