They had 3 children, not one:
1889 C6802 Rudolph Martin Eichmann Martin Friedrich Anna Maria Parchert
1891 C7683 Helena Augusta Eichmann Martin Anna Maria Parchert
1893 C7121 Hulda Martha Eichmann Eichmann Martin Friedrich Annie Mary (sic) Parchert
1900 C7321 Wilhelm Carl Gross Wilhelm August Anna Mary Parker
1903 C6172 Herbert Edward Gross Wilhelm August Anna Marie Parker
Marriage: 1922 C1043 Rudolph Martin Eichmann Edna Florence May Louis
Death: 1949 B24044 Rudolph Martin Eichmann Martin Friedrich Anna Maria Parchert
Funeral notice, Rudolf:
http://nla.gov.au/nla.news-article212745543Balmoral Cemetery, Location 4-279: Rudolf Martin EICHMANN, age 60 years
Date of Service: 27-09-1949
Service Type: Burial
Buried with him: Edna Florence May Eichmann, age 95, service date: 5-11-1997
Marriage: 1912 B12277 Helene Auguste Eichman Friedrich Willhelm Schodel
Death: 1973 B44616 Helena Augusta Schodel Martin Eichmann Anna Maria Parchert
1953 B46119 Friedrich Wilhelm Schodel Carl Friedriech August Marie Louise Wagner
Funeral note for Friedrich:
http://nla.gov.au/nla.news-article217169184Marriage: 1919 B22778 Hulda Martha Eichmann Samuel Herbert Wood
Death: 1965 B77647 Hulda Martha Wood Martin Friedrich Eichmann Annie Mary Parchert
Marriage: 1927 B1433 Wilhelm Carl Gross Emilie Elsie properly Amelia Elsie Brauer
Death: 1959 B34571 Wilhelm Carl Gross Wilhelm August Anna Mary Parchart ** late Eichmann
1979 B93144 Amelia Elsie Gross Christian Wilhelm Friedrich Brauer Wilhelmine Ernestine Kriedemann
Hemmant Cemetery, Brisbane: Lawn 1/324
Wilhelm Carl Gross 59 Years 17-10-1959
Amelia Elsie Gross 73 Years 17-01-1979
Marriage: 1928 B3636 Herbert Edward Gross Else Elenore Stollznow
Death: 1975 B63060 Herbert Edward Gross Wilhelm August Gross Anna Marie Parker
1979 B95543 Else Elenore Gross Johannes Martin Stollznow Martha Anna Ida Tesch
J.