"... His mother, Catharina Hertweck, also immigrated, and died in Milwaukee. She was my great-great-great-grandmother ..."
Was she the Catherine Bastian (88 yr) that died in 1934? (or was her married name Hertweck). There was an obit, but no death notice, in the local German newspaper for that person.
Some other surnames referenced with Bastian in these papers in a local index are: Davis Abraham Schmeling Bittmann Kron.
"Milwaukee's German Newspapers; an index of death notices and related items" (1844-1950).
Gary Rebholz, compiler/editor
Indexing Milwaukee's German newspapers continuously since 2007... helping to access our historic German-American culture.