According to the California Death Indexes Delmar Wayne Bennett (m) died 1997-04-15 in San Diego County, California. He was born in Wyoming 1935-09-05 with SS# 520-360-761 Death Indexes indicate his mother's maiden name was 'Best'.
I looked for other Bennetts born in Wyoming with same mothers maiden name 'Best' to no avail.
I checked the Social Security Death Indexes and could not find an entry for him by his name, SS#, or death date.
I would suggest you obtain a death certificate from California.Also do a post at the San Diego County board.Might have some there also do a OBIT lookup now that you know his death date. You'll have more luck there.