In 1940 he was forced to return to Switzerland due to World War II, leaving his own work and his collection behind. Much of the former was lost to theft or destroyed, but the collection was held up by French customs, and was preserved intact, and at the end of the war he was able to retrieve it. He resumed his collecting after the war, eventually donating the collection to the city of Lugano in several phases beginning in 1985. He continued to work in a variety of media including sculpture, lithography, collage and painting; he also taught at the Kunstgewerbeschule in Zürich. He painted several murals, including one at the Government Headquarters in Bellinzona (1958) and another in the television headquarters in Comano (1975).
