I worked for a Munich based company for 5 years and my first boss had escaped from Dresden at the age of 10 with his younger sister - the rest of his family being killed by the allied bombing.
He clearly didn't want to like me, but one night we went out and drank and talked and his story came out with an apology for his behaviour towards me. Once I understood his history, I could understand his behaviour as that must have been an horrendous experience for a 10 year old.
We became good friends and are still in touch, ironically because he has a nice collection of English sports cars.
I think there is a need to talk about what happened if nothing else to prevent it from happening again.