You probably saw the Paul Kapusta on the Social Security death index? Born April 1915, died April 1971. It would be a good idea to send for his SS application, as well as his death certificate. In the 1920 census in Westmoreland county PA, there is a Paul Kapusta, age 5, living with his family, parents Michael Kapusta 41, Julia 38, both say from Austria (Hungary in the 1910 census), siblings Rudolph 17 (died Nov 1980 in Mahoning county OH), Julia 13, Michael 11, Margaret 9, John 7, Helen 2, and Joseph 10months. There's no way to tell for sure if this is the Paul you seek, unless you do some digging to make a connection, but this seems like a good candidate.
I am not related.