According to his death certificate, he was buried in Chewelah, WA. I checked the Chewelah memorial park and Chewelah Pioneer Cemetery but didn't find him.
The entire list of indexed Stevens' County Cemeteries is at interment.net/us/wa/stevens.htm .
You might find more information in his obituary. You can request a copy from the Washington State Library, sos.wa.gov/library/obituaries.aspx. They will scan the obit (if one was published) and email it to you at no charge but it takes about six to eight weeks. Successful Searching!