Complex sentence: One of Dorman-Smith's two brothers, Eric, was a major-general in the British Army in the Second World War; after falling out with the British establishment, Eric he became an Irish nationalist sympathiser and changed his name to Dorman O'Gowan.
Split into simpler sentences: One of Dorman-Smith's two brothers, Eric, was a major-general in the British Army in the Second World War. After falling out with the British establishment, he became an Irish nationalist sympathiser and changed his name to Dorman O'Gowan.