Complex sentence: In 1941, at the age of 56, Roberts re-joined the military and spent four years in the Army during World War II. He was discharged with honors and returned to Chicago where he worked in media/public relations until his death in 1952.
Split into simpler sentences: In 1941, Roberts rejoined the military, serving in the Army for four years during World War II. He was discharged with honors. After returning to Chicago, he worked in media and public relations until his death in 1952.