The family of 12-year-old Archie Battersbee have vowed to “fight to the end” after filing a last-minute bid to have him moved to die in a hospice “with dignity” rather than in a hospital.

Doctors treating the schoolboy for the last four months declared Archie to be “brain-stem dead”, prompting a lengthy but ultimately failed legal battle by his family to continue his life support treatment in the hope the unconscious boy would recover.

The European Court of Human Rights (ECHR) refused an application from the boy’s parents on Wednesday to delay any changes to his treatment, which is due to be withdrawn from 11am on Thursday.

The family are expected to attend the High Court in London later on Thursday for a hearing over their bid to transfer Archie from the Royal London Hospital to a hospice. The hearing is listed for 3.30pm.

Hollie Dance, the boy’s mother, said: “I pray that the High Court will do the right thing.

“If they refuse permission for us to take him to a hospice and for him to receive palliative oxygen it will simply be inhumane and nothing about Archie’s ‘dignity’.

“We will fight to the end for Archie’s right to live.”

She said she wanted her son to “spend his last moments” together with family privately.

Speaking to Times Radio hours before her son’s life support is due to be turned off, Ms Dance said that Archie’s loved ones have not been able to have privacy at the hospital, saying: “We can’t even have the chance to be in a room together as a family without nurses.”

She added: “There’s absolutely no privacy, which is why, again, the courts keep going on about this dignified death – why aren’t we allowed to take our child to a hospice and spend his last moments, his last days together privately?

“Why is the hospital obstructing it?”

She said: “It’s going be awful today.

“I woke up absolutely sick to my stomach. Like I just feel this hospital have so much to answer for and I don’t really know what else to say today.”

The child has been in a coma since he was found unconscious at his home in Southend, Essex, on April 7 and is being kept alive by a combination of medical interventions, including ventilation and drug treatments, at the hospital in Whitechapel, east London.

Ms Dance believes he was taking part in an online challenge at the time he became ill. He has not regained consciousness since.

Barts Health NHS Trust has said Archie’s condition is too unstable for a transfer and that moving him by ambulance to a different setting “would most likely hasten the premature deterioration the family wish to avoid, even with full intensive care equipment and staff on the journey”.

A High Court order made in July requires that Archie remains at the Royal London Hospital while his treatment is withdrawn.

A family spokeswoman said a hospice has agreed to take him, adding: “Hospices are well and truly designed for palliative and respite care.

“Archie is now obviously on palliative care so there is no reason whatsoever for him not to take his last moments at a hospice.”