The Washington Death Certificate Index:
Wert Case died 23 Nov 1917 in Everett, Snohomish Co, WA, age 58 years 7 months 12 days (11 June 1859), father Horace Case, mother Elizabeth.
--I've no proof this is the correct person. Do you have his parents names? A paragraph below identified his father as being "H.M. Case"
The WA Digital Archives: http://www.digitalarchives.wa.gov/default.aspx
A marriage on 20 January 1921, Joshua S. Corey of King County and Lillie E. Case of King County. Bride signed as Lillie Estelle Case.
--The 1920 Census for Veterans Home, Retsil Post Office, Kitsap County, WA
Joshua S. Corey, inmate, age 76, widower, born in Ohio to father born in NY, mother in England, a Confectioner/Institution (indicates he was making candy there).
--The 1920 Census for Veterans Home, Retsil Post Office, Kitsap CO.
Lillie Case, Employee, age 50, widow, born in Michigan to father born in NY, mother in Michigan. Sanitress/Institution.
The 1910 Census has his birth in Michigan to father born in New York, mother in Canada, married 9 years(1900-1901, census enumerated 11 May). Both able to read and write, renting a house.
--The next census page shows a John H. Bridges, age 31, a forester/timber that owned his account. While there is no proof, Case may have been working for him. There could have been many different saw mill companies having logging operations.
The 1900 Census, enumerated 25/26 June, 1900, Township of Haight, Ontonagon County, Michigan
Wirt Case, born April 1859 in MI to father born in NY, mother in Canada, common laborer, owned his house. Shown as married 10 years.
Lillie, born July 1869 in MI.
The US Special Census on Deaf Family Marriages and Hearing Relatives 1888-1895, identifies Wirt Case and Lillie Brown. Four pages.
Page one has marriage detail section, however is blank.
He identifies his father as "H.M." Identifies himself as deaf, attended school in Michigan in Elk Rapids, MI, entered in 1868, present address in Keno, Michigan, a farmer.
Lillie identifies her father as "Wm. S.", mothers maiden "Sarah Davis". Lillie identifies her name as "Lillie E. born 1869", no siblings. She identifies herself as Deaf from age 3, from Paralysis on brain. Attended school in Hungerford, MI, admitted age 10 in 1879.
Date of information, June 10, 1890, Signed L.H. LeFever.
--Original scan of these 4 pages is available if you do not already have them.
The 1870 Census for Elk Rapids does not show a person matching criteria.