Your grandmother was both brave and lucky. I read an account of a German woman who was with a group of refugees when she heard the news that Hitler had killed himself. She exclaimed, “Oh, thank God!” without thinking. An SS man shot her on the spot.
In the movie “Downfall” (yes the one of the Hitler parodies, a great film, BTW), in the final days in Berlin, they had thugs going around killing anyone who didn’t fight the Russians, even children, who refused, were shot.