 Lion's sister, Rosa, died in Vught concentration camp on 2 May 1943.Immediately after the end of the war, Lion became the head of the Youth Office in Bad Aibling, using his position to build up the Federation of German Scouts, and in October 1948 he was appointed the honorary president of the organisation.He became the driving force in the reconstruction of the Scouting movement, first in Bavaria, but later across the whole of Germany.