https://en.wikipedia.org/w/index.php?title=Andr%C3%A1s_Toma&...
He becomes a research interest after he is repatriated in 2000. (For the simple reason that before that he was believed to be just a non-verbal psychiatric patient. There are many of those.)
That is well after the dissolution of the USSR and the fall of the Iron Curtain.
"He probably took part in the joint German/Hungarian defence of Nyiregyhaza."
"Many of the wartime Hungarian prisoners were civilians, rounded up on the streets by the conquering Russian army and transported east in cattle-trucks to rebuild the Soviet Union. One in three of them died of cold, disease, and malnutrition."
The Soviets had different ideas of what "friends" meant.
A Polish man and a Russian man were walking on a road when they stumbled upon a treasure chest.
"What a fortune! Let's divide like friends!", exclaimed the Russian.
"Nah, let's just each have a half.", replied the less excited Pole.