Conversation so far:
Does Cosmo Kramer have any parents? Who are the parents?
Kramer was estranged for a long period from his mom, Babs Kramer. His dad never makes an appearance.
What about Cosmo Kramer's dad?
Kramer mentions that he is the last male member of his family, implying that his father had died.

Question: Did he have any siblings?
Self-contained rewrite: Did Cosmo Kramer have any siblings?