Query about treatment

Hi.. My father was taken to a pvt nursing home from a government hospital in emergency situation..he needed urgent dialysis that couldn't be done in the govt hosp so doctors suggested us to take him to pvt hosp for dialysis (he already had left ventricular failure and chronic kidney dysfunction). he was kept in icu and his dialysis was done after which he was better.. We were told that he would be shifted to ward in a day or two.. But his condition started worsening after that and he passed away after 3 days due to a cardiac arrest. It was a small nursing home..maybe Not equipped to deal with such complex patients.but they did not inform us or guide us to take him to a specialized hospital and he passed away.. Maybe due to their inefficiency. They didn't tell us what emergency treatment they did after the cardiac arrest. They didn't give us any papers.. Only the bills.. Its been almost 20 days..can I file a complaint against them That they didnt tell us they werent equipped enough Could you guide me what can I do?