Michał Elwiro had four siblings: the firstborn sister whose name is unknown, who died at the age of 5 in 1835, sister Wacława who died in 1860, older brother Erminio (1835-1876), who became a physician and sister Adelajda, whose married name was Kłopotowska. Erminio died in 1876, leaving two sons Władysław and Wiktor. Elwiro supported the education of his nephews and made bequests to them in his last will, as well as his niece Maria Kłopotowska, who managed his property during his stay in France.