Vincent Lambert, 38, looked destined to be taken off life support after the European Court of Human Rights last week backed France's decision that he should be allowed to die.
Lambert was left a quadriplegic with severe brain damage after a 2008 road accident.
His wife supports the move, but his devout Catholic parents and some of his friends insist he is showing signs of improvement.
But the judicial tug-of-war over his right to die has taken a new turn, just days after the European court's verdict.
Some of his friends and family who are against taking the man off life support uploaded a video to YouTube on Wednesday that they claim shows Lambert responding to them.
In the video, Emmanuel Guépin, one of Lambert's friends, speaks of how the patient is “responding” to his surroundings. Lambert's mother is heard on the phone telling him “the news is not good”, referring to the ruling from the European court.
Guépin notes later that Lambert “reacts very strongly” to his brother with facial expressions.
See the video here.
However, experts have slammed the video saying that it is “manipulative”.
One of these was Professor Eric Kariger, who had worked in the team that has cared for Lambert over the years.
He told French channel Europe 1 that he had tears in his eyes watching the clip, saying that Lambert was indeed “in a serious and irreversible vegetative state”.
“It's manipulative. It's disrespectful to the patient, his wife, and their daughter, who are unable to mourn because of the relentlessness that's coming from his own family,” he said.
Lambert's mother Viviane has argued that her son is merely handicapped and any attempt to stop life-sustaining treatment would amount to “disguised euthanasia” while his wife Rachel insists he would not want to be kept alive artificially.
The legal drama began in January 2014, when Lambert's doctors, backed by his wife and six of his eight siblings, decided to stop the intravenous food and water keeping him alive in line with a 2005 passive euthanasia law in France.
(Vincent Lambert's parents have been heavily involved in the case. Photo: Herve Oudin/AFP)
However, his deeply devout Catholic parents, half-brother and sister won an urgent court application to stop the plan.
The case ignited a fierce debate around euthanasia in France where it remains illegal despite recent efforts to ease legislation dealing with the terminally ill — a campaign promise by President Francois Hollande.
In March, lawmakers voted overwhelmingly in favour of a law allowing medics to place terminally ill patients in a deep sleep until they die.
The law also makes “living wills” — drafted by people who do not want to be kept alive artificially if they are too ill to decide — legally binding on doctors.
Assisted suicide is legal in Switzerland, the Netherlands, Belgium and Luxembourg as well as in the US states of Vermont, Oregon and Washington.