I ve always found it weird that Rohit & his dad r cold 2 each other while they are so warm & loving to the rest of the family.
Since Sippy was clearly uncomfortable when his wife was praising him may be Rohit's past is tied to his dad. May be his dad had an affair but did not publicly accept his lover. May be they had a kid a daughter. Rohit came to know this & befriended the girl who considered him as a good friend & brother. Sonakshi's car hits her mom & she tries desperately to reach her dad but he doesnt bother. Finally she calls Rohit as a friend asking his help. Rohit rushes to the hospital but unable 2 save her. The girl comes to know that Rohit is actually her half brother. She gets angry that her dad abandoned her mom & Rohit lied to her. So she slaps him.
Hence Rohit now hates his dad & he genuinely loves his half sister & hence his attempts to reach out to her.