Sir Thomas Bingham, the Master of the Rolls, said that when the court gives its judgment next week it is likely to dismiss claims that to stop feeding Tony Bland would amount to murder.
Mr Bland, now 21, suffered crush injuries in the Hillsborough football disaster in 1989, which starved his brain of oxygen and sent him into a Persistent Vegetative State (PVS) from which doctors say he will never recover.
His parents, Allan and Barbara Bland, say their son is condemned to a living death. Last month the Airedale NHS Trust was given approval by the High Court to end the artificial feeding.
However, because of the importance of the case - not only for the other 1,000 plus victims of PVS - David Venables, the Official Solicitor, appealed.
James Mumby QC, for the Official Solicitor, argued that to effectively starve Mr Bland to death amounted to murder and a breach of a doctor's duty of care. He said the High Court ruling had gone further than any English court in 'life and death' matters and warned against taking a further step on a 'slippery slope'.
The Airedale NHS Trust, supported by Mr Bland's parents, said that the ruling should be upheld and he should be allowed to die 'with dignity'.
Robert Francis QC, said that withdrawing the tube would not result in doctors starving Mr Bland to death but in their failing to avert his death, which would be caused by his injuries. He said that he had in many ways been reduced to the 'level of a machine which processes food'.
The case will now go to the House of Lords on 14 December for a definitive ruling.
Mr Venables said after the hearing: 'I'm awfully sorry the Blands have got to wait a bit longer but it's such an important point we have to go on.'