THE family of Ibrahim Halawa have said that his mother was summoned to the Egyptian jail where he is imprisoned due to his deteriorating health.
His family fear the teen may have inherited a heart condition from his father, Sheikh Hussein Halawa - Ireland's most senior Muslim cleric.
On Sunday his mother, who has been staying in Egypt since his arrest, received a phone call from the wife one of Mr Halawa's cellmates.
The man who is interred alongside the Dublin 19-year-old is a doctor and he passed word through his spouse that the teenager's mum needed to visit him urgently, his sister Nusayba said.
Her younger brother has been complaining of worsening chest pains during his time in prison.
His mother brought medicine and requested again that her son be allowed to see a specialist who can examine his heart.
"When she was there they refused to allow him something small to eat or a bottle of water which he is sometimes allowed [during visits]," Ms Halawa told the Herald.
"My mum was very upset when she saw him.
"She told us that he does not look well and that he is very down.
"She tried to bring him some medicine but wasn't allowed to and the doctor in the prison has said that he is fine," she said.
"He is in a lot of pain, both physically and mentally," Nusayba added.
"During the visit he told my mum that he has nothing left and asked her to pray for him."
His family fear that he will die in his cell if he does not get adequate treatment.
"We are worried because at least three people have died there because they didn't get the proper medical care.
"They [prison authorities] just left them until they died," his sister said.
Earlier this year Human Rights Watch released a damning report criticising the standard of medical care in the Egyptian penal system.
The report said that many prisoners interviewed by the NGO said that the prison doctors were often inexperienced or over-burdened.
Many of them had relied on advice from other prisoners and medicines provided by family members to combat illnesses while in jail.
The Halawa family say that they have offered to pay for a specialist to visit him in prison if necessary.
On top of his suspected heart problem, his sister said that Mr Halawa has not recovered properly from an injury he sustained during the protests.
He was shot in his left hand during the siege and the injury has not healed sufficiently and he is not able to open his hand fully.
Mr Halawa, then aged 17, was arrested during the Al Fateh Mosque siege in Cairo in August 2013.
Three of his sisters, Omaima, Fatima and Somaia, were also arrested but later fled the country when they were released on bail.
Mr Halawa is due to stand trial alongside 493 other defendants, but proceedings have been pushed back or adjourned seven times.
Last week the judge adjourned the trial because some of those accused were not present and scheduled an eighth court date for August 2.
Taoiseach Enda Kenny recently told the Dail that the teenager was facing lesser charges than some of those he is standing trial with.
Mr Halawa is being accused of being present in the Mosque and refusing safe passage from the mosque when it was offered, said the Taoiseach.
He has been receiving consular assistance for the past two years but his family have repeatedly said more can be done to secure his release.