I think this is be Frederick Cooper son of Seth E. Cooper who is listed in the 1911 census living on Symons Street in Mimico.
According to his attestation papers dated March 6, 1916 in Blind River, Frederick Cooper of Blind River, Ontario was born on January 27, 1891 in Collingwood, Ontario. He listed his father Seth E. Cooper, Deau Lake, Ontario as his next of kin. He listed his occupation as machine hand. He had no previous military experience. He was 25 years old and stood 5 feet 2 1/2 inches tall. He had grey eyes, black hair and a fair complexion. He was a Methodist.