Now that we are closer to the much awaited raaz, I am pretty sure its about Bani's mom. Coz in 26th June episode, when the doctor recognized Jai Walia (while treating Bani), he particularly mentioned this 'Peechli baar mein kaamyab nahin hau tha, par is baar mien kamyaab ho gaya' referring that this time he cud save Bani.
So it makes the picture pretty much clear that someone dies in that accident. But just another thought - the hospital where Bani's mom dies (presumably) and where Nishikant Dixit donated 10 Lakhs, that was Rustamji Hospital (sumthing like that) and the hospital where Jai met that doctor was Lifecare Hospital.
Lets wait and watch.
- Crazyfats