I see Robert L. Fisher in West Bend, Washington County Wisconsin with his parents in the 1880 census. Have you found him in any census records since then? If you do a search for Wilson J. Fisher, spouse Charlotte Case at wwww.familysearch.org
there are marriages for the other children but not Robert. Do you have obits for Wilson or Charlotte, that may list where he was at the time? What is your source for him dying by 1930?