Apollo Hospital — Negligence

Address:	700054
Website:	kolkata.apollohospitals.com

On My 9th 2016, my late father Dr. Ranen Biswas was admitted to Apollo Hospital in Kolkata with an infection for which he was being treated with antibiotics which didn't check the infection. He was admitted to a hospital where he had some respiratory issues but the doctors helped to stablize him. They suggested that he be taken to Apollo which was better equipped to handle such issues.
My father was brought inot the ICU which he was able to get into easily because of the recommendation of a doctor from the other hospital.
However, the doctor in charge didn't check him till later. When my brother queried he showed no urgency to check my dad and when he heard my dad was 90 years he was even less interested as if to imply he's lived a long life. Really? A doctor's duty is to save lives no matter the circumstance, the age etc.
Anyway, when my dad was admitted he was talking, smiling, eating and seemed to be recovering. On the 10th morning he was visited by a doctor colleague of his as well as my family members. He talked and even joked with my niece. My brother and sister in-law (both doctors) visited him that evening, made sure he had had his dinner and left around 10pm. Early next morning they were called because my dad was put on a ventilator. What happened overnight to cause this extreme procedure? My brother should have been called and asked for advice before putting my elderly dad on a ventilator. Our house is just 15 mins away from the hospital.
I want to know what happened. Even his doctor friend ( who is a renowned surgeon) said he couldn't have died so soon.
I really would like to know the final moments of my dad's life before he was put on a ventilator. He died on May 11th morning. Thank you and am anticipating a response.
My email is [protected]@hotmail.com and [protected]@gmail.com