Complex sentence: After the Partition of India, his grandparents remained in Pakistan while his parents moved to India and after relocating to Allahabad, Jabalpur and Saharanpur, they settled in Rajpur, Uttar Pradesh (in present-day Uttarakhand) in 1954.
Split into simpler sentences: After the Partition of India, his family too split into two-his grandparents remained in Pakistan while his parents moved to India. After living in Allahabad, Jabalpur and Saharanpur, they finally settled in Rajpur, Uttar Pradesh (in present-day Uttarakhand) in 1954.