Simon de Jong was a son of Michel de Jong and Naatje Polak. According to tradition he died as a consequence of the bombardment of Rotterdam. He passed 14 July 1940 and he was unmarried.
website wiewaswie.nl/death certificate 1940/3886 - d145v of 15 July 1940 and an addition of a visitor of the website.
The funeral records at the Jewish cemetery in Rotterdam reveal that Simon de Jong was buried there.