My uncle was with him in the Soviet Ukraine after the war (Russia had seized the Carpathian Ruthenia from Czechoslovakia) and came to the US with him in the ’60s. He was my mohel. The day he was niftar I was thinking about him before I heard anything.
He lived in Russia, Israel and Monsey NY. When he was in Israel he was a chavrusa of Rabbi Yitzhak Zilber, the famous Gadol of all Russian Baal Teshuva Jewry. Together they had a seder in the middle of the night for a ew hours.