Steffan, Stephan, Steffon (same name)

I have very little information on my husband's family. His father's name was John Thomas Stephan b. abt 1915 m. Frances Agnes Grzech b. 1929 they were married in Mahoney City, PA.
My husband's grandfather was (from Germany) John Steffan b. abt. 1890 m. Veronica. There children were John Thomas Stephan (spelling due to error in military records) Michael Steffon (spelling due to military record error) Stephen Steffan.

I would appreciate any information about this family.