1918-10-10: Ewing died in Wentworth County, Ontario on this date from unknown cause(s)..
It would not be unreasonable to assume that he was probably another 'Spanish Flu' victim and it appears that he died at home, with his family, in Hamilton.
The Canadian Government memorial website has him as Arthur Horace Ewing.
Ewing, Arthur Hall (or Horace) (Air Mechanic Class II)
Died 1918-October-10

Birth Date: 1889-September-26
Born: Durham, Muskoka County, Quebec
Parents: Mrs. Eliza Jane Hall Ewing & and the late William George Ewing
Spouse: unmarried
Home: Hamilton, Ontario
Enlistment:
Enlistment Date: 1918
Service
RAF
Unit
Sqn- Squadron (RAF)
Base
Rank
Air Mechanic Class II
Position
air mechanic
Service Numbers
170878, RAF