Oh my goodness!!! Thank you so much!!! What we have at this point:
Husband's mother was Anna or Hana Kuplikova (she went by both). The name on her headstone in Ponca City, Oklahoma is Hana Kuplikova Hart. She had remarried after she and my husband's father divorced. Birth -- October 4, 1928. Death -- August 29, 1972.
She told my husband that his first name (Matous) is the same as her father's, although it could have been her grandfather's instead.
She said that her father had been mayor, and also some type of foreign dignitary or diplomat or something.
My husband's brother is trying to find an old letter he had that had both the grandparents' names on it, but has not had that luck yet.
My email address is firstname.lastname@example.org
Thank you so much for offering to help!