"We have evidence of him responding," he said.
"No doctor, no biologist can keep a dead person alive for three months," Ali said, according to BBC News. "The body does not work without the brain."
"I'm a biologist, I know that. The body does not work without the brain," he repeated.
Pacholczyk said there could be merit to the father's claims.
"To the extent that these observations are a manifestation of upper brain coordinated functioning, the child cannot properly be declared 'dead' or 'deceased'," he said.
In January, high court Justice Nathalie Lieven had ruled that the boy's parents did not have an arguable case and doctors could cease the use of mechanical respiration.
Sir Andrew McFarlane, the most senior family court judge in England and Wales, said that Midrar no longer had a recognizable brain and there was no other conclusion to be reached other than to withdraw life support.
"The factual and medical evidence before was more than sufficient to justify the findings," McFarlane said.
Manchester University National Health Service Foundation said the boy's organs were deteriorating. He had never breathed independently. The foundation said continuing treatment was undignified and said the boy should be allowed a "kind and dignified death."
Lawyers for the foundation said three tests confirmed brain stem death.
Pacholczyk noted that the U.K. diagnostic focus on brain stem death differs from other medical standards around the world. He said "brain death, understood as the complete and irreversible loss of all integrated neurological function (including brain stem function) is a reliable way medical professionals can determine that a patient has died."
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The parents' own attorney has noted that the diagnosis of death in the U.S., Canada, Australia and elsewhere is based on "whole brain death," and not "brain stem death."
The appellate court's Feb. 14 ruling cited the testimony of a doctor which said the key point about the U.K. diagnosis criteria is that "no patient has ever regained consciousness or awareness following brain stem death" and that when the brain stem dies it is "impossible for a patient to breathe unassisted."
Pacholczyk reflected on the standards of care in such cases.
"Brain-damaged individuals are deserving of full respect, and partake fully of human dignity, equally as individuals whose brains are not damaged," he said. "They deserve to receive reasonable ('proportionate') treatments as much as anyone else."
At the same time, it must be "carefully assessed" whether certain interventions were "extraordinary" in Midrar's case. Catholic ethics does not require extraordinary medical care.
"The question of whether he eventually will, or maybe already has stabilized in his condition, such that only minor additional treatments beyond the ventilator will be required, will also be important to assess carefully," Pacholczyk said ahead of news that the boy's ventilator was disconnected.