"... Mary Adella (Della) SARGENT (1867-1928) who married Henry ZWEIFEL in 1894 ... Della and Henry moved from Porter County, Indiana to Wisconsin after 1900."
In case it's helpful to this family research there are death notices in Milwaukee's German newspapers for a Della Zweifel in Dec. 1927 (which is pretty close to 1928). There are 75 Zweifel entries or references in "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...