According to http://www.dalbydata.com both John Wilke and
Freda are buried in Riverside Cemetery in Wasioja in Dodge Co.

Freda was born in 1875 so I would also search the census
records for 1870, 1880. Ancestry also has the MN state census for the years that end in 5.

To request an obituary from the Dodge County Historical Society you will need the name of the cemetery as this is how the obituaries are organized.

There are members of the Wilke family still residing in the Dodge County area.

Wendy