Donald de Leeuw, a butcher by trade, served as a witness at the wedding of his brother Alfred de Leeuw to Sophia Noach. The wedding was performed at Westerbork transit camp on 3 May 1943. Donald de Leeuw signed the marriage certificate.
Record of marriage certificates of the Westerbork municipality, currently at the archives of Gemeente Midden-Drenthe in Beilen