In case it's helpful to your research there are just a couple of Siller entries in "Milwaukee's German Newspapers; an index of death notices and related items" (1844-1950).
Siller, Bertha J. H. (née Struve)
Siller, Emma (née Budde, survived by Charles)
Siller, Frank / Franz
Siller, Sarah M.
For more specific information contact:
Gary Rebholz, compiler/editor
Indexing Milwaukee's German newspapers continuously since 2007... helping to access our historic German-American culture.