The parents of a 12-year-old boy who was left in a comatose state after suffering “catastrophic” brain damage lost a court appeal Monday to stop doctors from ending life support for their son.

Three Court of Appeal judges delivered a ruling about what was in the best interests of Archie Battersbee, who was found unconscious at home on Apr. 7. His mother has said she believed he may have been taking part in an online challenge.

Doctors treating the teen at the Royal London Hospital believe he is brain dead, and say continued life-support treatment is not in his best interests.

His parents, Hollie Dance and Paul Battersbee, launched their appeal after two High Court judges agreed with the doctors.

One of the judges, Justice Anthony Hayden, described what had happened to Archie as a “tragedy of immeasurable dimensions” but said medical evidence was “compelling and unanimous” and painted a “bleak” picture. He said continuing treatment would only protract his death.

The three appeal judges on Monday dismissed the parents’ attempt to overturn the lower court’s ruling.

Dance argued that she had seen indications that Archie, who is attached to a ventilator, had twice tried to breathe independently in the past few days.

But appeal judge Andrew McFarlane said medical staff had seen “no signs of life” in Archie.

McFarlane and his two fellow appeal judges said they would delay the ending of Archie’s treatment for 48 hours after his parents said they wanted to ask the European Court of Human Rights to consider the case.

(AP)