Zwick's obituary is online from the Hartford (Connecticut) COURANT:
Zwick is survived by his father and step-mother Frank and Lynn Zwick of
Myrtle Beach, SC, his sister Joan Zwick of Tolland, brothers David of Old
Saybrook, Douglas of Los Angeles, and their families.
If you are asking about translating WEAPONS OF SATIRE, at the time Zwick
published that book, some of the essays were still under copyright. Zwick
had plans to reissue the book which had fallen out of print. However,
shortly before his death he told me that Harper, who owned the copyrights,
wanted too high a price to grant permission to reprint the material and he
had abandoned the idea of reprinting the book. Thus, I think anyone who
wished to translate and reissue the book would not only have to deal with
the Zwick estate, but possibly with Harper, the owner of the original
copyrights to those particular essays.