Archie Battersbee 's mother has said she feels "extremely let down" by the justice system after a decision was made to end her son's life support.
On Monday, a judge ruled that Archie's life support can be turned off after his family lost a last-ditch bid to keep him alive.
The 12-year-old's family learned of his fate during an emergency Court of Appeal meeting, in which the President of the Family Division, Sir Andrew McFarlane, reinforced it was in Archie's "best interests" to have life support removed.
Speaking to Good Morning Britain on Tuesday morning, Archie's mum Hollie Dance said: "I'm pretty sure this is our last chance now.
"Me and Archie's dad made a promise to Archie we would fight this until the end and that's exactly what we intend to do."
Speaking from the Royal London Hospital in Whitechapel, east London, Ms Dance continued: "I do feel extremely let down by our justice system.
"I know Archie's still with us and Archie's showing very different signs to what the clinicians are saying," she told GMB hosts Richard Madeley and Kate Garraway.
"He's progressing in so many ways. He's got a very good stable heart beat, he holds his own blood pressure, he's gaining weight."
Ms Dance then admitted: "I haven't even had the chance to process what's happened with Archie, how I found Archie. Theres been no time to process anything, it's just been to fight for my child's life from day one really.
"I've done nothing but educate myself on brain injuries. He was squeezing my fingers so tight, they were red. He's opened his eyes, he's attempted to breathe. All we're asking for is time. The brain is a complex thing," she added.
Ms Dance then said: "I find it very hard not to exhaust every option. Whilst he is progressing, it's very, very hard not to fight for his life."
Referring to the medical professionals, Richard asked: "Why do you think they're so insistent? Why would they be so adamant?"
"I don't know, all I know is in every other country they've got very different options available to people," Ms Dance replied.
"He hasn't been given long enough, this is a brain injury. People stay on ventilators for a lot longer that Archie's had."
The judges rejected his parents' plea but granted a short stay, or delay, until midday today. After that, his ventilator can be switched off.
Speaking on Monday, Ms Dance said cutting off the life support - scheduled to happen at noon on Tuesday - would not be fair to her son.
She said: "I've got my son's best interests at heart - Paul, and the siblings - nobody else has got Archie's best interests at heart.
"And I say, and I still stand by it, Archie's best interests would be to allow that child time to recover. If he doesn't recover he doesn't recover, but give him time to recover."
Good Morning Britain airs weekdays at 6am on ITV and ITV Hub.
