In addition to the parents, John and Agnes Cook, William also had a younger brother, Charles B. Cook. If there are any relatives of either of the brothers who would like to make contact, I would like to hear from you.
I also found that William served in Langress,France during WWI. He was in Company Four, 1st Air Services Mechanics Regiment. He was listed in this regiment at the following address: 209 Blanda St. Utica, NY.