Who is Zvi Litvinoff from The History of Love and what is their importance?

Zvi Litvinoff is a childhood friend of Leo Gursky and Alma Mereminski. He writes obituaries for a local paper in Poland, taking great pride in his work. By sheer coincidence, Zvi and Leo reconnect at a café and re-establish their friendship. The two men discuss politics, writing and other topics. When Leo takes ill, it is Zvi who cares for him. During his visit, Zvi discovers that Leo has written his own obituary. He takes the piece with him as a sort of good-luck charm, thinking it will ward off death for Leo.