Thomas Braun's maternal grandfather, Rudolf Weber (1867-1925), was the son of Bernhard Weber (1829-1899) and Anna Sophie Weber née Busse (1827-1900), with Weber ancestors dating back to the late 16th century. These Weber ancestors, based in the North-East German region of Mecklenburg, include the 'Amtshauptmann' (head of the district authority) Joachim Heinrich Weber (1757-1826), who became a literary figure in Fritz Reuter's Low-German novel 'Ut de Franzosentid', published in 1859. Other Webers were pastors, lawyers or businessmen. Many of them were involved in local politics and administration in various Mecklenburg towns and districts, prominently Joachim Christoph Bernhard Weber (1786-1859, son of the 'Amtshauptmann' and father of Bernhard Weber), who was senator in the old Hanseatic city of Rostock and co-owner of the Saniter & Weber company.

The Saniter family is related via Rudolf Weber's paternal grandmother, Catherine Sophie Weber née Saniter (1795-1872), wife of Joachim Christoph Bernhard Weber. The Lobeck family is related via Rudolf Weber's maternal grandmother Johanna Henriette Charlotte Busse née Lobeck (1790-1866), wife of Christian David Busse (1785-1843, father of Anna Sophie Weber).

Thomas Braun's maternal grandmother, Hedwig Weber née Fink (1867-1951), was the daughter of Hermann Fink (1833-1885) and Gustava Fink née Zeller (1833-1906), with roots mainly in Mecklenburg and Western Pomerania.