Final answer:
The Canadian officer in question is Pierre Le Moyne d'Iberville, who founded the first capital of Louisiana and died in Havana due to yellow fever.
Step-by-step explanation:
The experienced Canadian officer put in charge of establishing a fort in Louisiana, whose younger brother accompanied him, and who died in Havana, Cuba from yellow fever upon his return to Louisiana, is Pierre Le Moyne d'Iberville. Iberville was a French Canadian explorer who played a significant role in the colonization of French Louisiana.
He founded the first capital of Louisiana, Fort Maurepas (now Ocean Springs, Mississippi), in 1699. Unfortunately, Iberville's efforts were cut short by his untimely death due to yellow fever in Havana, Cuba in 1706, after visiting the Louisiana Territory he helped establish.