How can the death of a Tzaddik become a Kapparah?

The Tzadik is not a personal individual that has an impact only on him self, he is a public figure which impacts on all those around him; a loss of a Tzadik is therefore a public loss not an individual or family one. The Tzadikim are here not for themselves rather for others, that is how they live their lives and that is how they also die; Just as the death serves as atonement to the deceased himself, so the departure of a Tzadik does to his community.