Complex sentence: He reenlisted at the beginning of the war and suspended his writing career though he did manage to write some youth oriented war stories during the war under the name Frank W. Mason as well as publishing a couple of reworked pulp serials under the name Ward Weaver.
Split into simpler sentences: He reenlisted at the beginning of the war and suspended his writing career though he did manage to write some youth oriented war stories under the name Frank W. Mason. At this time he also published a couple of reworked pulp serials under the name Ward Weaver.