No, Finland handed both jewish and non-jewish Soviet POWs to Germany. Hundreds of people sent from Finland to Germany died in the camps. Finland also deported multiple jewish refugees to Germany, these people were neither Soviets nor POWs.
Yes, sure, Finland had it's own complicated reasons for behaving the way it did. There's however no serious dispute about whether or not Finnish collaboration in the holocaust happened.
I couldn't care less if this person's grandfather was a Nazi, even if it turns out to be true. What are they supposed to do, go back in time and convince their grandfather to change their ways? It ridiculous using this as some kind of insult, and it disturbs me that people might take it as one.
