Thomas was a seasoned soldier having seen many battles when he was wounded for the first time by a shell fragment in the right arm and gassed in the Battle of Hill 70 at Lens, France, on 18 August 1917.

Back in Canada, Thomas sustained injuries both from shrapnel and gas, but survived even though he lived with the effects of the gas for the rest of his life.

Thomas died on 14 June 1964 at Camphill Hospital, Halifax, Nova Scotia. He is buried in his hometown of South Maitland, Nova Scotia, Canada.

His brother, Frederick MacDonald, who died on 9 August 1917,

is buried at Bully-Grenay Communal Cemetery, British Extension.