Complex sentence: After suffering a stroke and the amputation of his right leg, Clark became an invalid, aided in his final years by family members, including his younger brother William, one of the leaders of the Lewis and Clark Expedition.
Split into simpler sentences: After suffering a stroke and the amputation of his right leg, Clark became an invalid. He was aided in his final years by family members, including his younger brother William, one of the leaders of the Lewis and Clark Expedition.