[1] During World War II, when Northern Transylvania was part of Kingdom of Hungary (see Second Vienna Award), Kahan and two siblings were able to obtain "Aryan papers" in Budapest.
After getting reports from his father in Sighet that Jews in the city were gathered into ghettos, he returned home to provide food.
After arriving in the camp, his mother and sister were murdered in the gas chambers; Kahan and his father were selected as workers.
He decided to stay and was granted permission to settle as part of the Jewish refugee quota established to replace the number of Norwegian Jews murdered in the Holocaust.
He was active in the Jewish community in Oslo, serving as leader of the Mosaic congregation (Det Mosaiske Trossamfund) for a time, was an active supporter of the Jewish Museum in Oslo, and was a board member of the Friends association of Norwegian Center for Studies of Holocaust and Religious Minorities.