Cancer patient Roger Lamb, 79, tried to help 76-year-old Ken Godward, who was being attacked by schizophrenic Harry Bosomworth, 70, on a ward at St James's Hospital, an inquest heard.
Mr Godward died on March 3, 2015, and Mr Lamb died sometime after the attack which happened on February, 28 2015.
Mr Bosomworth died of cancer in June 2015.
A six-day inquest into the deaths of Mr Lamb and Mr Godward started at Wakefield Coroner's Court on Monday (Dec 10).
The inquest was told Mr Bosomworth told hospital security staff he believed he had been attacking burglars who had broken into his home.
Mr Godward's daughter-in-law Lisa Dixon told the inquest that she spoke to Roger Lamb in hospital before he died.
Mrs Dixon said: "I went over to Roger to thank him for his bravery, of getting out of bed and possibly stopping Ken from getting killed there and then.
"Harry was that upset he was out to really do some damage on these two gentlemen.
"He (Roger Lamb) just said anybody would have done it lass - I couldn't lay in bed and not try my best, but unfortunately I didn't do enough.'"
Mrs Dixon told the inquest that the attack was "definitely avoidable," adding: “Our lives have been on hold since.
"I don't think the NHS has taken into consideration the families who have been ignored, it's damningly wrong.
"Harry is not a perpetrator, he is a victim."
The inquest was told the attack happened after Mr Bosomworth woke from a Lorazepam medication sedation following his aggressive behaviour.
Senior Coroner Kevin McLoughlin read a statement from healthcare assistant Karina Rojo, who said that Mr Bosomworth had previously been shouting and swearing on the ward
Ms Rojo wrote in the statement that at around 6.55am she checked Mr Godward's and Mr Lamb's blood pressure
Ms Rojo wrote: "Harry was naked and still shouting, I can't remember if it was this time or a little before, but I remember him saying to me he was going to rape and kill me."
Ms Rojo said she went to raise concerns about Mr Godward's blood pressure and oxygen levels with a nurse, adding: "I was about to continue with my rounds when I heard a loud bang.
"I saw Harry raise his stick a number of times and hit Roger. I don't know how many times, it was so fast.
"He raised his walking stick above his head and hit Roger. I grabbed Harry and restrained him on the floor."
Nurses then noticed blood on retired postman Mr Lamb's face as he was laid on a nearby bed on ward J19 at James's Hospital, where he was being treated for bowel cancer.
Reading a statement from hospital security officer Andrew Hall, coroner Mr McLoughlin said Mr Bosomworth was taken into a television room at the hospital
Mr Hall said Mr Bosomworth told security officers: "They were trying to break in my home. There was five of them. I got three of them, they won't do it again.
"I think he believed we were police officers, he kept saying they were trying to get into the house. It was as if he was trying to justify what he had done. He appeared confused."
In a statement read out on behalf of security officer Carl Webster, he described how the ward was "chaotic" and staff were in tears.
Reading the statement, Mr McLoughlin said: "Staff had their heads in their hands as if they didn't know what to do."
The inquest heard nurse Susan Carter had started work at 7.30pm the previous night and was coming to the end of her shift when the attack happened.
She told the inquest there were two nurses and two healthcare assistants working on the ward dealing with "possibly" 29 patients.
Nurse Carter said she was told by staff on the previous shift that Mr Bosomworth was unsettled and had not taken his medication that afternoon.
She said that Mr Bosomworth was upset and an attempt was made to give him his Lorazepam tablet orally, but he wouldn't take it.
Nurse Carter said she called a doctor to ask for an injection to be prescribed and two security staff and two health staff were needed to restrain Bosomworth and give him the injection at 9.30pm.
She said the injection worked and he went to sleep in about 20 minutes.
Nurse Carter said Mr Bosomworth woke at 3am and she gave him another tablet, which she said she believed he had taken.
Nurse Carter said that after the attack she saw Mr Lamb on the floor.
She said: "He was in shock but he wasn't crying. He did seem to be in discomfort. Kenneth did have tears on his face when he was laid in bed. He did start to cry."
The inquest heard Mr Lamb died from a chest infection due to a fracture of the right hip which ultimately occurred as a result of blunt force trauma.
Mr Lamb's close friend, Daniela Loeb had visited him in the days after the attack and prior to his death on March 3.
She questioned whether sufficient concern had been shown by staff for him and fellow patient Mr Godward's safety before the attack.
Miss Loeb said: "Terrible things happen in life and you cannot always anticipate them.
"There were significant indications that Harry's behaviour was deteriorating, that he had to be sedated because of his deterioration, behaviour and aggression.
"As a result, once this sedation which had gone through his body, he started to behave once again in a very aggressive, deluded fashion.
"I was absolutely shocked I had not been given this information prior to that information coming to light.
"Whether there was sufficient concern shown by staff for Roger and Kenneth's safety given the circumstances."
GP Sarah Nathan told the inquest: "Every time there was a lapse in medication there was a risk that his condition would worsen and an increase in thinking people were looking at him."
Pathologist Kirsten Hope said Mr Godward died from sepsis due to pneumonia with underlying Alzheimer's.
But she told the inquest he would not have died when he did had it not been for the injuries sustained from the attack.
The inquest continues.
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