I think he was buried at the Hospital which was usually the case for hospitals like this one. Unfortunately people were generally buried in unmarked graves or graves marked with a number in cement. Then the records to convert the number to a name were lost.
Spencer State Hospital, www.wvculture.org/history/government/spencer03.html
Spencer State Hospital Cemetery, www.findagrave.com/
I'd contact the Roane County Historical Society
\PO Box 161
Spencer 25276-0161 and ask about how to find a copy of his obit. It also might have been published where his wife was living. Successful Searching!