A 12-year-old boy who was declared "brain dead" after collapsing at his home "would have wanted to fight to the end", a court heard.
Tragic schoolboy Archie Batterbee suffered a "devastating" brain injury at home in Southend, Essex, on April 7.
His mother previously said he may have been taking part in the dangerous "blackout" social media craze, where people choke themselves until they pass out.
Archie's parents want his life support to continue in case he miraculously recovers and are locked in a legal battle with the Barts Health NHS Trust, which is looking after him him, who say his treatment should be stopped.
Doctors treating him at the Royal London Hospital in Whitechapel, east London, told a High Court hearing last month that he was "brain-stem dead", adding medical interventions should end and his ventilator should be turned off.
Mr Justice Hayden, who is presiding over the case at the Court of Appeal, said: "He would have wanted to fight as long as he was able to for his mother. That he would want to fight to the end seems to me to be pretty clear."
But he added that "fighting to the end" implies the prospect of overcoming his predicament, of which "there is no prospect here".
The Court of Appeal was told Archie and his mother had a brief conversation one or two years ago where he said he would like to remain alive as a vegetable if he ever found himself in such a situation. He is said to have told his mother: "I wouldn't care, I wouldn't feel anything."
Lawyers acting for the trust said those words do not rule out the prospect that switching off his life support was in his best interests.
Martin Westgate QC, representing the trust, said earlier that Archie is "unresponsive" and has no prospect of recovery.
Last month the High Court heard he was "brain-stem dead" and that life support should be switched off but his parents successfully overturned the ruling.
Ian Wise QC, the family's lawyer, told the court the youngster would want a "natural" and not "choreographed" death.
He said in his closing submissions: "What you can be sure of is that he would not want to upset his mother and father and that their wishes would be considered to the utmost. He would have wanted their wishes to be respected.
"We can't have a casual consideration of his best interests without giving full force to the sanctity of life. This treatment is not futile as it does what it sets out to do."
He also said Archie had Article 8 right to a private and family life under the European Convention on Human Rights, which is codified into British law under the Human Rights Act.
Martin Westgate QC, representing the trust, said in his closing submissions that carrying out more medical procedures would be futile.
He told the court: "One aspect of dignity is not to carry out extensive procedures where they are futile and cannot infer possible benefit to the patient.
"There is no realistic prospect of recovery and his treatment is invasive, and will become more so as it continues. It is desperately sad but he is never going to get better.
"The parents want there to be a miracle. The suggestions they are making are ones that are desperately wishing for more time."
A judgement is expected to be handed down at the same court on Friday morning by the judge in person.
