Junker, sorry for the delay, this campaign seems to have been largely forgotten and information is hard to come by.
Anyway, I've managed to come up with very little solid info, but my Air Force contacts tell me that
no patrols were flown by civilians at any point.
Your grandfather flying for Cruzeiro is quite fascinating. Cruzeiro was formed in January 1943, up until that point it was known as Syndicato Condor and flew the Junkers Ju-52 and Focke-Wulf FW200 Condor. With Brazil moving closer to the Allies, the airline changed the name, replaced staff to remove any German influence, and began changing the aircraft type in February of 1943 to the DC-3. However I have seen timetables* from 1944 with the Tante Ju and the Condor on the cover, so it is possible that your grandfather was flying a German aircraft, in a previously German owned airline, in support of military operations
against German forces.
It would be interesting of the family could find your grandfather's logbook, that would be a good read.
And it seemed such a simple question at the beginning .....
*
Cruzeiro - Servicos Aereos Cruzeiro do Sul - Syndicato Condor