May be Bani's grand parents might come to know that Bani is his grand daughter if they come accross KD's jewelery which Bani sold to get money. May be they will meet Jigs's friend who bought the jewelery & tell them she got it from MRs. Jai Walia. I bet that jewelery belongs to Singhanias Bani's dad came from poor/ midle class family.
BTW why didn't Bani sell er other jewelery given by Walias. or better still what happened to the jewelery given by moti Ma during the wedding ? She can sell that.