Fawzi al-Odah of Kuwait asked his lawyers during a meeting last week to file court papers seeking the removal of his feeding tube "out of desperation" over his imprisonment without charges, attorney Tom Wilner said on Tuesday.
"He is willing to take a stand if it will bring justice," Wilner said.
The lawyers have not filed the motion because they first want al-Odah to get the approval of his family and doctors not affiliated with the US government, Wilner said.
Al-Odah's family does not want him to starve himself to death and they are "frantic" about the situation, the attorney said.
Al-Odah, a 28-year-old who was arrested in Pakistan in 2002, weighed 139 pounds three years ago and is now down to 112 pounds, according to government records cited by his attorneys in court papers.
"If it gets to the point where he says 'I want to die' and his parents say no, then we have a conflict"
Al-Odah's request raises a number of ethical and legal issues, including whether his lawyers would be able to continue representing al-Odah and his parents if they disagree on whether to file the motion seeking removal of the feeding tube.
"If it gets to the point where he says 'I want to die' and his parents say no, then we have a conflict," said Wilner, the lead attorney for 11 Kuwaitis held at Guantanamo and a partner in the Washington law firm of Shearman and Sterling. "We could represent one or the other but not both."
Al-Odah's request for an order seeking the removal of his feeding tube was mentioned in a footnote in court papers filed in Washington by Wilner as part of an effort by defence lawyers to gain more frequent access to their clients, copies of their medical records and to allow the prisoners to speak by phone with their relatives.
The US military has said that it considers hunger striking a form of suicide and will take whatever steps are necessary to prevent any detainee deaths at the prison where the government says it holds 500 men on suspicion of links to terrorism.
Unnecessary loss of life
Detainees are closely monitored
by medical professionals
Guantanamo spokesman Lieutenant-Colonel Jeremy Martin said the military would not comment on specific cases, but that it was Department of Defence policy to prevent "the unnecessary loss of life of detainees through standard medical intervention ... to overcome a detainee's desire to harm themselves."
There are 26 detainees participating in the hunger strike, which began on 8 August, including 23 who are being force-fed through nasal tubes, Martin said.
"The detainees are clinically stable, closely monitored by medical professionals, and will continue to receive appropriate nutrition, fluids, and excellent medical care," he said.
Guantanamo officials have said this latest hunger strike began with 76 detainees protesting against their confinement.
Defence lawyers have cited other reasons as well, including complaints about food and water, alleged abuse by guards and interrogators, and their desire to either face trial or be released.