You can order a copy of his death certificate from south Dakota Health Dept., http://doh/sd.gov/VitalRecords/genealogy.aspx
. Hopefully the Informant knew where and when he was born and who his parents were. If they did, it will appear on his death certificate.
It appears that he might have been previously married according to the Smith Family Tree, http://trees.ancestry.com/tree/23547168/person/1400390787
Joseph G. Smith b. June 19, 1884 Storm lake, Buena Vista, Iowa. Married to Maria Mercedes Smith b. Adair, Iowa and died 29 April 1938.
Their Joseph G. Smith died 13 Oct 1944 in White, Brookings, South Dakota.
However, family trees have been known to be incorrect.
In 1930 in Oak Lake, Brookings, South Dakota there was a Joe G. Smith, wife Mary and several children living in Oak Lake.
The Brookings Area Genealogical Society, 515 Third St., Brookings, SD 57006 might have a copy of Joe's obituary. Successful Searching!