Sorry so long in replying, William died in 1905, so the 1911 census could not be him.
William H. Trewartha
BIRTH 16 May 1854
DEATH 2 Feb 1905 (aged 50)
BURIAL
Harriston Cemetery
Harriston, Wellington County, Ontario, Canada
PLOT CC-3-34
MEMORIAL ID 237099588 · View Source
Abraham and Elizabeth had a total of 6 children, only the 3 girls married, Catherine to John Waters , 1877, Elizabeth Jane to William Chapman pre 1888, and Mary to her 3rd cousin Wiliam Knight Trewartha, in 1902.
the 1911 census was Mary and William Trerwartha, with their adopted son, William and biological son, Not sure who Leonora is, born 1888, William and Mary were not married till 1902.
Have to do some work on that one.
Thanks again for all your help.