Cardinal O’Brien – who resigned as Archbishop of St Andrews and Edinburgh in 2013 after admitting sexual misconduct – was visited by his successor, Leo Cushley, on Saturday, his 80th birthday.
The cardinal has been in the care of the Little Sisters of the Poor in Newcastle, but was admitted to hospital in the city after a fall in which he broke his collarbone and also suffered a head injury.
On Friday night, Archbishop Cushley sent a message to more than 200 “brother priests and deacons” to tell them of Cardinal O’Brien’s deterioration before visiting.
Archbishop Cushley said: “I went to see him a few weeks ago and he barely recognised me, although at that time his life did not appear to be in danger. However, his condition is not improving and he may not have long to live.
“If this situation continues, and if he is able to be moved, he will be taken to the Little Sisters of the Poor to receive palliative care. Please remember him in your prayers.”
Cardinal O’Brien resigned after admitting his sexual conduct had at times “fallen beneath the standards expected of me”.
Three priests and a former priest had made allegations of improper behaviour against him dating back to the 1980s, including inappropriate contact.
Prior to his resignation and his retirement from public life, the cardinal, who was born in Ballycastle, Co Antrim, had been the Archbishop of St Andrews and Edinburgh since 1985. He was made a cardinal in 2003.
In his resignation statement, he said: “In recent days, certain allegations which have been made against me have become public.
“Initially, their anonymous and non-specific nature led me to contest them.
“However, I wish to take this opportunity to admit that there have been times that my sexual conduct has fallen below the standards expected of me as a priest, archbishop and cardinal.
“To those I have offended, I apologise and ask forgiveness. To the Catholic Church and people of Scotland, I also apologise.”
He added: “I will now spend the rest of my life in retirement. I will play no further part in the public life of the Catholic Church in Scotland.”
In 2015, Pope Francis accepted a decision by Cardinal O’Brien to formally give up his rights and duties as a cardinal.
Cardinal O’Brien has been living in Northumberland since his resignation five years ago, in a house owned by the Church.
He is understood to have suffered a fall last month in which he broke his collarbone.
Cardinals lose the right to take part in future papal elections, and carry out the other responsibilities of their rank, on their 80th birthday.