Lefebvre and Havy's business grew steadily, as they personally handled cargos and eventually came to own a small ship of their own, the Parfaite Union.
They experienced a setback when they invested in a sealing station in Labrador with Louis Bazil and Louis Fornel, and retained their interest in it until the 1745 capture of Louisbourg by Anglo-Americans cut them off from it.
In 1756, during the Seven Years' War, Havy returned to France to oversee the transfer of as much of the business as possible there and Lefebvre joined with another cousin, François Levesque, as a partner to conclude what business remained.
When the British captured Quebec in 1759 much of their assets in New France—in mortgages, Canadian paper money, and bills of exachange—were declared worthless by the new government.
In 1760 he finally set to return to France, but died in an accident at sea aboard the Trident.