His parents are listed on his death cert. as Joel McCowan and Mary Cowan. You might want to try to get an original to see if there are more details. Maybe Mary is the dau. of Richard and Eleanor?
Illinois Deaths and Stillbirths, 1916-1947
Citing this Record: "Illinois Deaths and Stillbirths, 1916-1947," index, FamilySearch (https://familysearch.org/pal:/MM9.1.1/N3F8-T87
Name: Ernest A. Mccowan
Death 02 Jan 1921 Granite City, Madison, IL
Male Age: 36
Birth : 08 Dec 1884 , MO.
Father Joel Mccowan Birthplace: MO
Mother Mary Cowan Birthplace: Mo.
Occupation: Carpenter
Residence Place: Granite City, Ill.
Burial Date: 05 Jan 1921
Burial Place: Greenville, Missouri