Baby RB suffers from a rare, genetic condition
A doctor has agreed a baby in a "right-to-life" legal row may be able to interact - but any mental development would only make his fate more tragic.
The paediatric neurologist told the High Court the severely disabled child, Baby RB, would remain in a "no chance" situation even if he developed further.
He questioned the life the boy would lead if he was capable of cognitive function but physically so disabled.
The boy's father is fighting an attempt by the hospital to end life support.
The hospital is supported by the mother, who agrees with the lawyers who say her son will lead a "miserable, sad and pitiful existence", even if surgery allows him to be returned home.
Instead, they say they are seeking permission to withdraw fundamental life support "to allow him a peaceful, calm and dignified death".
One-year-old Baby RB suffers from a rare, genetic condition called congenital myasthenic syndrome which makes it impossible for him to breathe independently.
Dr M, as he is referred to for legal reasons, said further development would make Baby RB's life "even more unbearable". This, he said, was "the tragedy of it".
Martin Westgate, counsel for the father, showed a video of the baby apparently smiling and responding to a toy balloon and doll. This, it was suggested, was evidence he was capable of purposeful movement.
Dr M said he was "still not convinced" from the video the baby was displaying conscious "volitional" movements, but under questioning agreed this was possible. "Yes, I do accept that," he said.
However he said he did not believe small changes in muscle function would improve the boy's quality of life.
A year-old-child should be able to play peek-a-boo with his parents. Baby RB, he said, had "never got anywhere near anything that was clinically significant".
He also noted that the child had developed curvature of the spine as a result of his prone position, which would only get worse and lead to other problems.
'On a knife edge'
Baby RB's father believes he might be taken off his ventilator and returned home if surgeons carried out a tracheotomy, which creates an opening in the neck to deliver air to the lungs.
His doctor has agreed to carry out a tracheotomy assessment on Saturday and report back to the court next week.
On Tuesday, another clinician - Dr F, a paediatric intensive care consultant, agreed with the boy's hospital and his mother that his quality of life was so low that it would not be in his best interests to try to save him.
He told Mr Justice McFarlane that Baby RB was living "on a knife edge" and could suffer even greater distress if a tracheotomy was performed and some sort of blockage or infection developed.
For legal reasons, none of the parties in the court case can be identified.
Both parents, who are in their 20s and are said to be "amicably separated", have been present at the hearings.
The hearing continues.