He is presumed to have continued to engage in fur trading in the west for the next 15 years; certainly he acquired a working knowledge of several native dialects.
He led 300 Caughnawaga Indians to reinforce the militia at Lacolle who were then transferred to Upper Canada in 1813 and based at Burlington Heights along with other native warriors.
Returning quickly to Lower Canada, Ducharme was placed under the command of Lieutenant-Colonel Charles-Michel d’Irumberry de Salaberry; for his participation in the Battle of Châteauguay on 26 October he was later awarded a medal and clasp.
On one occasion, according to the journalist Pantaléon Hudon, Ducharme’s Indians tracked down and captured six deserters from Salaberry’s unit; they were court-martialled and, on the lieutenant-colonel’s orders, shot.
Ducharme remaining years were spent in the quiet obscurity of Lac des Deux Montagnes, where he continued as interpreter for the Indian Department.