Complex sentence: Frank's elder brothers were Warington Baden-Powell and Sir George Baden-Powell, and he had two younger brothers Robert Baden-Powell and Baden Baden-Powell-and there was another brother Augustus (May 1849-March 1863) who died aged 13.
Split into simpler sentences: Frank's elder brothers were Warington Baden-Powell and Sir George Baden-Powell, and he had two younger brothers Robert Baden-Powell and Baden Baden-Powell. Another brother Augustus (May 1849-March 1863) died aged 13.