Great-grandfather from my father's side fought in Monte Cassino, in the actual successful take by the Poles. He told me that when they captured it the Brits wanted to take down the Polish flag that they hung up, and the Poles told them that they will shoot them if they try. True story. He also saw the famous soldier bear, Wojtek, pic related. He came back to Poland from the UK in '47 and basically as soon as he came off the ship, he was arrested and put into jail for 8 years. He was paranoid of the commies till the day he died.
The great grandfather from my mother's side fought against the Soviets, he was captured and sent to a Gulag, after he served his sentence he walked back from around the area of lake Baikal back to Poland. Then he was part of the AK (anti-commie underground army), killed a few Ukrainians and then participated in Operation Vistula where he forcefully migrated Ukrainians.
Both of them died peacefully in their beds sometime after Poland stopped being communist.