https://www.theguardian.com/technology/2017/sep/01/facebook-you-cant-block-mark-zuckerberg-priscilla-chan-too-many-already-have

On Facebook, the only member of the immediate Zuckerberg family you can block is Beast, their dog – plus Mark’s sister Randi

Bad news! You still can’t block Mark Zuckerberg on Facebook. And now you can’t block his wife Priscilla Chan either.