Yes, you can say that Jasmine did it, but the point is that Shamsher never discussed this event earlier. It was a sudden decision. Also, just before leaving the house, Naaz realised that they weren't attending the function. She had no time to call Jasmine. Therefore, the accident could have been planned by Jasmine, but who tampered with the brakes?
The vehicle had an issue, and the accident happened because of the brake failure. This is why I feel that it's all Shamsher's plan.
I don't think he will risk either of his son's lives.
Jasmin on the other hand is soo evil. She can go to any extend