But for starters: German refugees didn't flee to other countries. They fled (either because they were "bombed out" of their residences in the big cities or because the Soviets were invading) to other regions of Germany - where they were usually viewed with contempt, distrust, and at best pity by the local Germans. Also, they received minimal support from the State.
Read "The German War," by Nicholas Stargardt.
Regards,
But for starters: German refugees didn't flee to other countries.Immaterial. They were still war refugees on the run for their lives. Whether it be for shelter or safety from shooting/bombing/etc.
As to how they were treated. Regardless of what you read many were taken care of. Maybe not by government, as that had collapsed due to losing the war. I have read accounts of even soldiers getting clothes from civilians so they could blend in and avoid detainment.