Try to ask at www.dinkelsbuehl.de
On the left side you will
find "Online Dienste", then scroll down for "Standesamt"
"Urkunde Geburtenregister". The Standesamt, where a person
was born, has the dates where a person died. So you have
the "Bezirk" of Berlin. I hope this will work for the
time 1938. Or do you know in which cemetery he is buried?