I didn't know your grandfather.
F: W. D. Gentry
Married: 5 Sept 1918
F: Isaac Smith
M: Ellen Br
Source: KY Marriages 1785-1979
Born: 1934, Madison, KY
M: Mannie Smith
Source: KY Vital Records Indexes 1911-1999
Buried: Springboro Cemetery, Springboro, Warren, OH
That's all that I found.
The Warren County Genealogical Society, www.co.warren.oh.us/genealogy/obitsmain.htm
has his obit. It's listed as Floyd Gentry but the death date was Feb 1940.
You can order a copy of his death certificate from the Ohio Historical Society, Archives Library, www.ohiohistory.org/learn/archives-library/death-records
. Successful Searching!