Catherine's father appears not to have been particularly interested in his parents' family connections, a point that was driven home to me last year when I discovered that his mother had (until 1940) a sister living in Winnipeg, of whom he himself (when I asked him about her) seemed unaware. I have since come into possession of a good number of handwritten letters from that sister to his mother, as well correspondence from France and newspaper articles that have (collectively) allowed me to flesh out some of the history.
Jean Baptiste Homard (born 1852), a "well-known contractor in northern France", married Marie Claire Vassel (born 1857) and they had (in 1879) a daughter, Marie Isabel [Jeanne] (anglicized to Mary Elizabeth [Jane], that unknown sister). Jean Baptiste and Marie Claire were on the steamer Labrador, arriving in New York (from Havre) on 28 Jul 1886. A daughter, Emélie Matilde (anglicized to Emily May, Catherine's grandmother), was born 1 Apr 1887 in Fort William, Ontario. Another daughter, Gabrielle, was born in 1889 — supposedly back in France. Marie Claire's mother, Catherine Bouquet Vassel (born in 1826) ended up back in Canada with them in 1891 (according to the 1911 census). Gabrielle died of scarlet fever (in 1903) in St. Norbert, Manitoba.
Jane had married Albert George Cowley in 1898 in Winnipeg and they ended up with three children: two boys with mostly-known, living descendants and a girl without offspring. Here they are (sans daughter, plus pet dog) circa 1910:
By the time Emily married Frank Powers (3 Jul 1912) in Calgary, Alberta, Jean Baptiste and Marie Claire Homard, and Catherine Vassel, had returned to France — to Thiaucourt. At the start of World War I, they became prisoners-of-war, ending up in Frankfurt-am-Main, Germany. Catherine died a year or so into her incarceration. Marie Claire and Jean Baptiste survived "well, but hungry" and were released at the war's end. Marie Claire died 12 Dec 1923 and Jean Baptiste, 5 Apr 1924. An 8 Apr 1924 letter to Emily from a cousin, Jeanne Vautrin in Thiaucourt, gives details of Jeanne's family, including a photograph circa 1920:
The Vautrin children are Jean (born ~1906), Michel (born ~1913), and Marie Blanche (born ~1915). The masculine-faced, dark complexioned adult in the photo must be Jeanne because her husband, Alfred François Vautrin (1 May 1880, Beney-en-Woëvre - 20 Aug 1914, Bréhain), would have been dead. Jeanne also mentioned a sister, Marie. Chances are good that there are living descendants in that part of France.