His Death Certificate (computer extract) is online via Family Search Records.It is specific that he died at: Sedro Woolley, Skagit, Washington.I found 24 Family Trees posted having him included, full name Cornelius Huff Cain.Elizabeth is identified as death 10 Sep 1925 in Union, Mason County, WA.Daughter Martha Rosetta Robison, died 31 Jan 1951 in McKenna, Pierce Co, WA.The Tacoma Library database of obituaries identifies her date of death, her obit was published on 1 Feb 1951, page 34.(You can obtain their obits also, see below).The other child died at/after birth in 1866.
My point, I found 24 family trees posted that identified him.A couple of them appeared to be accurate and somewhat complete.The rest were inaccurate (died in Mason County), or far from complete.None of them identified WHERE he was buried, some did say in Seattle.Since none included the information you requested, I did not contact any of them. I "assumed" you already had the basics of him and his life/death; but when you post be specific on what you know and what you need.
Unless you have the records, it is unknown exactly when he may have been sent to this hospital, sometime after 1910, before Oct 1916.But, since his death certificate identifies he was buried in Seattle, I would "guess" this was due to his being of this area and owning property.
In the 1910 Census he and Elisabeth were living at 1722 West 57th, in the area of Ballard (Mostly a Scandinavian neighborhood).The Census identifies that he OWNED the property in Seattle.
One of the closer cemeteries to his property, the Lake View has a burial index; but his name was not listed. The likely site: The Evergreen-Washelli Cemetery, is a VERY LARGE cemetery just north of his residence on the Aurora Blvd (a major north/south arterial) (I just happened to have driven by it on Friday).It has a genealogy form that can be used for research.This website does not say that EVERY request for a name is a genealogy search, or a genealogy search would result in records.BUT, they charge $10.00 for this genealogy search.http://www.evergreen-washelli.com/locate/http://www.evergreen-washelli.com/locate/ I would "suggest" calling or emailing them just to ask if he is buried there, just a name search.If they say they charge $10.00 just for that, I would then ask them if you would receive all records in their control for that amount.If you email, try the "general questions" address of Info@Washelli.com
As to other cemeteries in Seattle, a majority of them are not transcribed, some have minimal transcriptions.
Before paying the fee for research (for ANYONE), I would first suggest attempt to obtain his obituary via the Washington Library Service, a FREE service: Contact them at: http://www.secstate.wa.gov/library/ask.aspxhttp://www.secstate.wa.gov/library/ask.aspx .