Complex sentence: On 13 August 1910, he succeeded to his childless brother's (John Spencer, 5th Earl Spencer) titles, and died 12 years later at his home in St James Place, London.
Split into simpler sentences: On 13 August 1910, he inherited further titles, including the earldom, on the death of his childless elder brother, John Spencer, 5th Earl Spencer. He died 12 years later at his home in St James Place, London.