Mr Justice Collins said the 24.5 hours of care laid on by the council for Still's Disease sufferer, Daniel Heffernan, is 'not at all generous' given the devastating extent of his handicaps.
But the judge, sitting at London's High Court, stopped short of condemning the council's stance as 'irrational' - although he directed Sheffield to reconsider Mr Heffernan's care plan.
He said the council was no doubt 'trying to do its best' for Mr Heffernan, of Broomhall, Sheffield. 'It has its own resource difficulties and, no doubt, other deserving cases,' he observed.
But the judge said Mr Heffernan's condition is ever-detiorating and his case would have to be kept under close review.
Mr Heffernan, said the judge, is 'almost totally blind' and suffers from Still's Disease, a type of rheumatoid arthritis 'characterised by high spiking fevers'.
Both his hips and knees have had to be replaced and the replacements are coming close to failure so that further major surgery is likely to be needed.
Mr Heffernan suffers 'regular flare-ups' which cause him severe pain only alleviated by sterod injections. The pain can be so terrible that he vomits and can do absolutely nothing for himself for 24 hours.
Major flare-ups have been increasing in recent months and even more minor episodes make Mr Heffernan incapable of basic activities like washing, dressing or lifting objects for a few hours.
The judge said Mr Heffernan, through his solicitors, had been complaining to the council 'for some time' over the inadequacy of his care regime. They say his condition is now so acute that care must be available 24 hours-a-day in the form of a live-in carer.
In February this year, Sheffield carried out a fresh assessment of his needs and said he needed 24.5 hours care each week.
But Mr Ian Wise, for Mr Heffernan, attacked the assessment as 'piecemeal and formulaic' and said the council had 'irrationally' failed to take a 'holistic approach' to his care needs.
However - despite some 'errors' in the care plan - the judge said he was 'not persuaded' that there had been a failure to properly assess Mr Heffernan's needs.
He observed: 'I am bound to say that the amount of care is not at all generous. But it does not have to be: It must be adequate to meet his proper needs.'
The judge said the council would have to reconsider Mr Heffernan's care plan in the light of the errors he had identified, 'but I cannot say that that reconsideration will inevitably result in more hours of care.'
'While I would not be surprised if it did, I cannot say that the present allocation is perverse.'
Mr Justice Collins said he appreciated his decision 'may not be regarded as particularly helpful to either party', but concluded: 'I am not prepared to say that the care plan is perverse, albeit I think that it must be reconsidered.
'That should obviously be done as soon as is reasonably possible.'
Earlier, Mr Wise told the judge the lack of adequate care provided to Mr Heffernan had left him isolated and depressed. He argued that only a 'live-in' carer would be adequate to meet his practical needs.
In a harrowing written statement before the court, Mr Heffernan said the flare-ups in his condition can trigger such severe pain that he vomits and 'cannot speak properly'.
'My lack of care means that, even between flare-ups, I do not have enough care to enable me to do basic tasks. I need assistance and supervision with everything.
'I need to be able to have a carer to be able to be on hand urgently at any time of the day or night and to be able to stay and provide as much as I need to remain safe.
'I have been in a state of desperation for many months now as a result of my condition and my inability to get support to do essential daily activities and to remain safe in my home.
'I have felt so desperate at my isolation and neglect that I have rung up the Samaritans on a number of occasions.'
STRAND NEWS SERVICE