Brogan Larkham was born 14 weeks premature in December 2006 at Antrim Area Hospital to parents Kelly and Ben, who were teenagers aged just 14 and 15 at the time.
The child was immediately put on life support but appeared to improve.
Brogan was treated for a number of infections before being transferred to the Royal Victoria Hospital for Sick Children in January and given surgery so that he could receive the medication he needed.
He was supposed to be returned to Antrim but his condition continued to worsen and he was then diagnosed with septicaemia - blood poisoning - and put on a life-support machine.
The baby's condition was now critical and the machine keeping him alive was switched off on 3 February.
"I wanted to keep him," Kelly told UTV. "Watching him pass away in my arms was awful and there was a monitor in his heart that kept going down and when it got to zero it kept going up again.
He was everything, we had so many plans for our Brogan for the future.
"It did it for ages then it stopped."
Kelly and Ben said they always felt their son's care could have been better, but they never expected the full extent of what they now know.
An investigation by the Commissioner for Complaints, Tom Frawley, has exposed a series of failings at both hospitals which led him to conclude that, while undoubtedly Brogan may have succumbed to his other complications, his death could potentially have been prevented.
The report found that staff at Antrim Area Hospital had failed to identify that Brogan had sustained a broken collar bone.
He was wrongly diagnosed with fungal meningitis and staff failed to tell the Royal that the infection which led to the septicaemia had spread all over his body, the investigation said. There were also mistakes in the recording of urine samples which left results open to misinterpretation.
Kelly said: "That's what hurts the most - these are the people that are supposed to look after our baby."
The most damning criticism was of the Royal Belfast Hospital for Sick Children which failed to recognise early signs of infection and did not start appropriate treatment at the earliest opportunity.
The report also said Brogan should have been treated in the neonatal intensive care unit instead of the paediatric intensive care unit.
We would be pleased to meet with Brogan's parents to discuss his findings.
Kelly said: "I nearly fainted with the news, my legs went to jelly and I couldn't walk."
Ben added: " We weren't really expecting to be told that - we went in with our complaints but when that came out in the final report it just really shocked us."
In a statement, the Northern Trust said it "cannot comment on the case because of ongoing legal proceedings" - a civil action taken by Brogan's parents.
Meanwhile the Belfast Trust said it is extremely sorry that some aspects of Brogan's care fell short of what should have been expected, adding that they are willing to talk to the family.
It said: "We understand that the loss of a child in any circumstances is devastating for families.
"We are extremely sorry that some aspects of Brogan's care fell short of the standards of care that would have been expected. This case is now subject to legal proceedings."
Kelly said apologies will not bring their son back.
She added: "When Brogan passed, I haven't been the same person since. I haven't looked at things the same way. They say time is a healer but for me it's not, the pain is with me every single day."
Kelly and Ben now know their son could possibly have survived - but they only found that out because of their own persistence.
Since Brogan's death there have been changes and the already embattled health minister has promised more, and brought in the former Chief Medical Officer for England to move forward.