I also found him in 1935 with his wife and assumed it was the right man.
The address for the above was 152 Oakcrest Ave. He had the same address when wife Agnes passed away on 16 Oct 1938.
Looking through the old Toronto directories found at
https://www.torontopubliclibrary.ca/history-genealogy/lh-digital-city-directories.jsp :
1941
Sydney living at 66 Oakcrest Ave
Living at 152 Oakcrest is Ernie Gook
1942
Sydney back at 152 Oakcrest and Ernest at 28 Oak Park Ave
1943
page folded blocking the names, but don't see oakcrest, although I can see Ernie's occupation, so I don't think Sydney is listed.
1944 only Ernie is listed.
A long shot, but wife Agnes is buried at
http://www.stjohnsnorwaycemetery.ca/ They do answer genealogical requests, so it might be worth asking if Sydney is buried with her. At the bottom of the link is an email address for genealogical requests.
There is a Sydney Gook listed at deceasedonline.com (just in case he took a trip to the UK and died there):
Last name Gook
first names Sydney
Cremation date 07 December 1960
Location Lancashire
You would have to register, and cost of viewing the cremation document (which has his address etc) is £2.00