The smartest thing Abdullah could do is to pin this on Nayef's incompetence. He could even make it a religous thing if he wants. He could say that Nayef has failed to protect the kingdom and failed God. That would work.
Replacing them could be messy. However, THEY may leave us with no other choice...........and given the choice between the precious soverignty of a bunch of medieval homicidal neaderthals and our survival, I'll take us any time.