I think you will find that There were two Augustin Brabants
Augustin Brabant was married to Angelique Lussier, had a child Angelique Brabant who married Alexis Nault. Their daughter Justine Nault married Felix Dumont who was married to the first Nancy Perreault (daugher of Adolphe Perreault) - See Indian Territories History Records and MNC database.

This Augustin also had a son named Augustin Jr. Augustin Sr. Died before 1830. I'm trying to trace back Augustin Sr.