Misjudgement in Drunken drive causing fatal accident

Hello, I'm writing this to get some legal guidance regarding the drunken drive incident, in which my father got killed. The incident happened in August 2011. In a few weeks, we filed a case in City Civil court through an advocate. We owned a truck which my father used to drive. It was during a routine journey back to the city that a back tyre got busted, and my father parked the vehicle towards the side of the road, as much as possible. Then, while he along with a helper was looking at the tyre, an share-auto which came speeding from behind dashed on the standing person, causing grievous injury. My father died at the spot. The autorickshaw dashed against opposite side of road and the persons inside got away with minor injuries. Later the driver was nabbed, and was found to be in an inebrieated condition. The police took the statement of the helper, who is a relative of ours, and filed an FIR against the auto driver. The helper wrote a statement for the FIR, where he highlighted that the driver was in an inebrieated condition. But when the police person re-wrote the FIR, he seems to have deliberately left out the note about the driver being drunk. The helper tried to convince the police to include such information, but they seemed to have tactfully denied stating only the events should be noted in the FIR. After it was almost 4 and a half years, our relative, and a couple of other eye witnesses to the incident received summon from the magistrate 'fasttrack' court. Eager to get justic now at least, we headed to the court. Only after the main witness - the helper was inquired - we came to know that the wind was blowing in the other direction. The auto driver's lawyer was bent over proving that the person was not the one involved, while we were shocked to know that not a word on the driver having driven in an inebrieated condition was ever brought out. Moreover, they seemed to have not made any note of my relative trying to explain such a condition, but took only yes or no's for answer, just to hasten up the work. The whole thing dawned upon us, that either the police had no intention of exposing the 'drunken' condition of the driver, or had obtained a bribe to hide it. It is not clear what procedure they're supposed to follow to check blood alcohol level of the driver after the incident. We do not know if they never put him to the check or they're simply hiding the report. We're feeling dejected and heartbroken. Even after losing a life and that for a unfair reason, we were not given justice. There seems to be too much foul play where an entire system of law and justice is acting the opposite of how it must. We were later told, we won't be needed to appear at the court any more. But then, it is heart wrenching to know that such an reckless drunkard could do so much damage and could still get away with it, as if it was just some common accident. I'm sure that if it hadn't been for the police's hand, he'd have received maximum punishment. Haven been given no choice, we're now convined the situation has gone out of our hands now. But anything we can do to put the rascal to justice - an appeal or dispute, we're ready to do. Please advise. Thanks!