Medical negligence

My father was admitted in hospital for fainting on 26.12.23 and subsequently passed away on 2.1.24.He was diabetic and hypertension with ckd.However he was ok first four days and after third dialysis to reduce potassium levels he was unconscious and before this he was put tube for feeding. He regained consciousness after ventilator support and next two days high fever and again unconscious.last day pulmonologist visited to say that he had aspiration pneumonia which was acquired in hospital as the day one chest x ray was clear. However in his death summary report nothing was mentioned about this and only fluid overload was mentioned as cause of death.When queried hospital authorities and treating doctors refused that they never told aspiration pneumonia.As we have the x ray of all days and myself being a veterinarian,and after consultation with outside experts, it was confirmed as pneumonia.He was admitted for low BP and subsequently died of pneumonia which hospital covered up.Now after frequent follow ups,requesting for all patient records through email as pdf document,doctor denies telling that online theft of patient data might happen ,if mailed.They are demanding to intimate a day in advance and then Cole in person to collect the records.As per medical council rules 1.3.2, within 72 hours of request the doctor is supposed to handover treatment records.I want to know 1.can I force them to send pdf of record only through mail as it is safe 2.Or should I directly send a legal notice to submit the records to us through mail 3.With the records available with me ,I can say that the pneumonia is hospital acquired. 4.The change of version by doctor that he didn’t have pneumonia and not to record the same in death summary. 5.The only possibility of aspiration is stomach contents entering lungs when was unconscious and hospital refused to give CCTV footage of iccu. Kindly let me know how to proceed legally for their negligence in improper records,misconduct not to give records through mail,negligence causing death.