This person is commemorated on a memorial in Appingedam. More information on this memorial can be found (in Dutch) on the website of the Nationaal Comité 4 en 5 mei.
Heiman Akker was a son of Izak Heiman Akker and Leentje van Gelder. He was married to Judikje Zwart, a daughter of Izaak Zwart and Carolina van Gelder. The couple had five children: Izak, Carolina, Henriëtte, Aron Jacob and one child that presumably resided at another address and survived the war. The family lived in Appingendam right beside the synagogue. Addition of a visitor of the website.