Simon Keizer married Saartje Marcus in 1902. The couple had two children: Carolina and Soes Manus. The family lived at 6 Burgemeester Royerplein in Hasselt. Simon Keizer was a scrap iron merchant.
Simon Keizer and his wife Saartje Marcus were deported to Sobibor from Vught via Westerbork.
H. Hamburger and J.C. Regtien, Joodse oorlogsmonumenten in de provincie Overijssel, alsmede algemene oorlogsmonumenten waarop joodse namen voorkomen. Profiel (Bedum 2002) 40
In addition, a Jokos file (number 54368) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.