I don't find him in Ancestry's Army Enlistment Database nor the NARA online database to get a year of birth. In 1930 census there are 2 Henry Markowski living in Detroit MI, one born 1922 with parents and 2 older sisters and one b. 1913 with two older brothers and younger borther and sister. The AMBC website has Henry C. Markowski. Have you tried to get a look up of the Detroit local papers for an obituary?