There's bit more to it than one appointment, Every time Saisbury was in a position to do so, he promoted his nephew to yet another, higher, post. And the greatest post, Prime Minister, was awarded to Balfour on Salisbury retiring as Prime Minister. The expression 'Bob's your uncle' was , reportedly, known in Whitehall talk in Balfour's lifetime but not it was not put into print until Balfour was, conveniently, dead and therefore could not sue for the libellous innuendo in it.