Heather,
There is an entry for what I think is your relative on the
www.volksbund.de website:
http://www.volksbund.de/graebersuche...DDF936BBCF35B2
If indeed he's the Rudolf Morgenstern of your research, then the date he was officially reported missing was 10.9.41, so just a few days after his plane was lost.
Website says that his remains haven't been brought to a German cemetery, nor could be retraced as yet. They presume he's still buried at/around Pustinia, Russia.
Regards,
Leendert