Doctors have told the High Court that an 11-year-old boy who suffered catastrophic brain injuries in a collision less than three months ago, will make only a minimal recovery.

The High Court heard it was likely the boy was experiencing pain and intensive care interventions could leave him in a worse condition.

The hospital he is being treated in, wants permission to withhold invasive interventions and administer palliative care, but this is opposed by his parents.

A paediatric intensive care specialist told the High Court, the boy had already exceeded expectations by surviving what he had come through. 

But the doctors treating the boy say his brain damage is irreversible and he is in a vegetative state.

They say he is unlikely to recover much further and his body is likely to deteriorate.

His best prognosis they say, would be to move to a minimally conscious state.

The hospital is looking for orders from the High Court allowing it to withhold invasive interventions such as resuscitation and administer palliative care.

It says invasive treatment to prolong the boy's life would not be in his best interests and after coming through such treatment he may be in worse condition than he is now. 

But his parents, who are estranged, both oppose this. They say it's too soon after the accident and want him to have more time. 

The court was told the boy suffers from involuntary stiffness of his muscles, which is being controlled to an extent with medication. A neurologist said she was 90% sure he was experiencing pain as a result of these episodes.

The court heard the mother described her son as having the heart of a lion.

She also said he was a home bird and would get comfort from being home and having his beloved dogs near him. She wants him moved home or to a nearby hospital.

Ms Justice Mary Irvine asked the hospital for more information about the boy's episodes of muscle stiffness. 

She will hear more evidence tomorrow, including testimony from his parents.