Complex sentence: Between 1943 and 1944, he teaches sculpture to the School of Art of Braunschweig; however, he comes back to Austria from bombardments undergone by his native country and where he dies, in 1945, from a disease of the loins.
Split into simpler sentences: Between 1943 and 1944, he taught sculpture at the School of Art of Braunschweig; however, he came back to Austria because of the bombardments that his native country had undergone. There he died, in 1945, from a disease of the loins.