We have established that the Bonbardier on your dad's plane was Stanley Schwartz, and his ASN for a Flight Officer is T-125730.This information correlates to NARA POW database information for the date of the aircraft loss.
My MACR-guy verifies the name and POW status of Stanley Schwartz via official contemporary documents.
My alternate resource verifies the serviceman with the above ASN is: Schwartz, Stanley T-125730deceased NOV98 (DOB 12MAR23)
Cross reference to SSDI shows the following: STANLEY SCHWARTZ DOB:12 Mar 1923 DOD:21 Nov 1998 Last Residence: 11235 (Brooklyn, Kings, NY)
If you wish to pursue contact with his family you would need to research around the 21NOV98 date for his obit in Brooklyn.That would have to be a pin point search because there are quite a few Schwartz's in Brooklyn---sort of like looking for one guy name Flynn in Boston.