This was Donald Mack McCoy (Warren and Gene McCoy's Dad). He was born to George McCoy, age 23 and Bertha Ann Woods, age 18 on July 21, 1911. His birth certificate lists his father as a farmer and his mother a housekeeper. He was born in Lamar, Texas in Hughes County.
His had two grandsons - Donald Mack McCoy (named after him) and Michael Ray McCoy.