Mohammed Asghar's female lawyer cannot be named for fear of reprisals and asked for anonymity owing to what her colleagues say is "the nature of the case and to security concerns in the country".
The 69-year-old, who lived in Edinburgh until a few years ago, was arrested in 2010 in Rawalpindi, near the Pakistan capital, Islamabad, for claiming to be the Prophet Muhammad - despite being mentally ill. He has already attempted suicide in jail.
His family say he was treated for paranoid schizophrenia at Edinburgh's Royal Victoria Hospital before he travelled to Pakistan four years ago. He was convicted last month and sentenced to death, and is now languishing in a seriously overcrowded prison in Rawalpindi.
This week, an open letter signed by politicians and academics called for Asghar to be released so that he can receive treatment. In an interview, his Pakistani counsel said he remains severely ill.
"He is highly delusional and does not understand the meaning of his sentence," Asghar's counsel said. "He remains entangled in his grandiose delusions and can make little sense of what is happening to him. He does not act like a man who has been sentenced to death, because he does not fully grasp what that means.
"Due to a lack of adequate medical or psychiatric care, he is not being treated for his mental illness nor is he being provided the treatment outlined by his Scottish psychiatrist."
Adiala Prison, where he is being held, "is a grossly overcrowded prison with several inmates stuffed into a cell made to house two", she said. "He is currently sharing a cell with three other prisoners who are also facing blasphemy charges or convictions."
The lawyer said: "He has never complained to us about a lack of food or water. But the fact that he is not being treated for his mental illness is just as dangerous as being denied food or water. The jail authorities have neither the insight, capacity nor willingness to provide him with adequate treatment.
"The sanitation conditions at the jail are terrible, with several outbreaks of tuberculosis in the past. There is a toilet in each cell but it is uncovered and with no privacy so the cell-mates have to defecate in front of each other.
"He is able to communicate with us as we visit him every Thursday in the prison. His family [in Pakistan] are also allowed to visit him, but his family in the UK cannot telephone him because the prison does not have any facilities."
Asghar has complained in the past about his cell-mates. "In my last meeting with him about two weeks ago, he was getting along much better with his cell-mates," his lawyer said. "In the past, the constant presence of other prisoners around him would lead him to retreat into his delusional state even further."
Asked what kind of person she had found Asghar to be, the lawyer said: "In my experience of representing Mr Asghar, he has always been in a very fragile state.
"I have seen his health sharply decline in the past year, where his lucid periods have become far less. He has always been, with myself and the rest of our team, the most gentle person. He always greets me by placing his hand over my head, a sign of fatherly love."
The lawyer also voiced her thoughts on the way Asghar's case had been handled by Pakistan's judicial system - and the risk to court officials working on such a case, including herself.
"Since this issue is an extremely highly charged one in Pakistan, with a real threat of violence attached to it, it is virtually impossible for the judiciary to dispense justice.
"When you look at the fact that all court proceedings become public record, that creates an immense amount of pressure on all the actors involved, especially the judges, not to look like they are being lenient to a blasphemy defendant.
"Unless and until the proceedings are placed before a special court in which the entire proceedings are under seal, there can be no justice dispensed in such cases."
On being asked if there is an expectation he will be executed, or if political and diplomatic pressure will have an effect on his situation, she replied: "For Mr Asghar, at almost 70 years of age, with his physical and mental illnesses, it is very unlikely that he will survive until his appeal is heard - which is an average of five or six years.
"Keeping that in mind, the UK and EU governments should be concerned about the very real possibility of his death behind bars and do everything they can to ensure that he returns to Scotland for medical treatment."
A SPOKESPERSON for the legal charity Reprieve, which has been assisting Asghar, told the Sunday Herald: "Mr Asghar remains a very ill man, and we're continuing to push the UK and Pakistani governments to work towards his speedy release to ensure he gets the medical attention he needs."
A Scottish Government spokesman said: "We are concerned about this case and are in contact with the Foreign & Commonwealth Office and Mr Asghar's family, who will keep us informed of the situation.
"The Scottish Government strongly opposes the death penalty in all circumstances. As a minimum, we would urge the Pakistani authorities to abide by the moratorium they have on the death penalty."
The Foreign Office has said it has continually made representations to the Pakistani government on behalf of Asghar and would continue to do so.
In a statement released through Reprieve, Asghar's family said: "We are really upset and concerned that they will never release him and that he will die in jail. He has already attempted suicide unsuccessfully.
"We just want him back home where hopefully he can be treated for and recover from his mental illness. We urge the British government to intervene and bring him home to us where he will be safe."
A petition on website change.org, calling on David Cameron and Alex Salmond to intervene, has attracted almost 29,000 supporters. Amnesty International has called for his immediate release.
On Friday, the Pakistan High Commission in London said the Pakistani government could not interfere in the country's judicial process, and that Asghar was receiving the appropriate medical treatment. A spokesman hinted there was hope of an early court appeal, a process that can take up to five years.
Asghar's problems in Pakistan started over a property dispute with a man in Islamabad. The man reportedly showed police officers letters written, but not sent, by Asghar in which he claimed to be the Prophet Muhammad.
One section of Pakistan's penal code allows the imposition of the death penalty for blasphemy - but the principles of both Sharia and Pakistan criminal law say a mentally-ill person cannot receive a death sentence.