Complex sentence: Born to Father Janakinath Bose and Mother Prabhavati Bose (née Dey) in Calcutta on 6 September 1889, he was a child of a total of fourteen siblings, the brother of Subhas Chandra Bose and the maternal uncle of Prabhat Ranjan Sarkar.
Split into simpler sentences: Born to Father Janakinath Bose and Mother Prabhavati Bose (née Dey) in Calcutta on 6 September 1889. Sarat Bose was the brother of Subhas Chandra Bose and the maternal uncle of Prabhat Ranjan Sarkar.