Not completely our fault.

Me and my family were going to Chandigarh from Delhi in Amabala where there is a flyover my dad took the wrong way we had to take the flyover instead of the Link Road so we did not go very far it was just 30-40 meters so we decided to reverse the car and go to the flyover , we were standing at the extreme left of the road. We waited until the road was empty for us to go and when there was no car coming we started moving but when we were about to climb the flyover we had to stop because there was a car coming so we were half on the flyover and half on the road then suddenly an auto rickshaw came with full speed, over loaded passengers and a gas cylinder in it and banged with our car and it turned upside down. It was not even our fault. By chance the police also came there. The people who were inside it said to the police that it’s the rickshaw drivers fault and people who were watching the rickshaw driven on the road also saw it driving at an high speed and also told it to the police officer. Only 2 people were injured out of which one was a lady in her 50s and second was an old man in his 70s and the son of the old man has filed a case demanding compensation. We also have a third party insurance. He has filed another case after 3 months demanding for compensation of Rs. 40 lac. Inspite of the fact that he had spent only 10 lac. (What he says) On the pretext that his father died because of the accident but it was a natural dead and even the post-mortem was not done of the old man. The ipc sections on my father are 279, 337 &338. Now he also wants to add section 304. Is there anything which can be done. Please help us. And one more thing no where in F I R launched it is written that thethe auto driver banged into our car everywhere we have been made the culprit.