Hi Wendy,
in Social Security Death Index, I found;
MARY A ZELNY 29 Aug 1913 Dec 1988 (Clinton, Worcester, MA)
IGNACY ZELNY 17 Jul 1911 Jan 1969 (Clinton, Worcester, MA)

Also phone and address;
- for Cazimir?;
C Zelny - 978-365-6851
399 Water St
Clinton, MA 015102326
- for Jose;
Jos Zelny - 978-368-0115
28 Wilson St
Clinton, MA 015104220

Cordially,
Wladyslaw