You may already have this information, but in Edward G. Mason's Early Chicago and Illinois - Chicago, 1890 (Chicago Historical Society's Collection, vol. IV)we read : Two of Pierre Ménard's brothers, Hypolite and Jean-François, followed him to Illinois and settled at Kaskaskia. The former was a successful farmer, and the other a famous navigator of the Mississippi. Both led useful and honored lives, lived to advanced age, and both rest near their brother Pierre in the old cemetery at Kaskaskia. A nephew, also, Michel Ménard, having as well the family patronymic of Brindamour, who was born at LaPrairie, December 5, 1805, made his way to Illinois at the age of eighteen. For several years he was employed by his uncle Pierre in trading with Indians. He obtained great influence among them, and was elected chief of the Shawnees. It is said that he almost succeeded in uniting the tribes of the Northwest into one great nation, of which he would have been king. In 1833, Michel went to Texas, was a member of the convention which declared its independence, and of its congress. A league of land was granted to him,including most of the site of the City of Galveston, which he founded, and where he died in 1856. It is related that the Indians said of him, as of his uncle Pierre, whom in many respects he resembled, "Ménard never deceived us."
I hope this can be useful for your search. I am still looking to see if I am related to Pierre. My maternal great-grand father was Napoléon Ménard, married to Rose Thibeault on Oct. 5, 1886 at age 27 in Oscoda Michigan. If in the course of your research you find any connection, please let me know.