Mother: Reunion with US man jailed in North Korea 'emotiona
The mother of American Kenneth Bae, who is imprisoned in North Korea, told the BBC his health had improved following two months of medical treatment.
But Myunghee Bae said her worst fear was that he would get sent back to a labour camp.
The Korean-American was arrested last November and sentenced to 15 years' hard labour in May.
Mr Bae, described as a tour operator and Christian missionary, was accused of plotting sedition.
Mrs Bae was allowed to visit her son - who is reportedly suffering from a series of ailments including diabetes, an enlarged heart and back pain - on 11 October
In an interview with the BBC, Ms Bae said she was not initially worried when she first heard the news that her son was arrested.
"He always told me he was welcomed in North Korea. He brought tourism over there that helps the economy," she said, adding her son wanted to change the perception of North Korea to the outside world.
Kenneth Bae was transferred from a labour camp to hospital earlier this year as his health deteriorated.
Mrs Bae said she was trying to hold back tears when they met, and both of them were very emotional.
"But my heart was aching when I saw him in a hospital garment, confined in a small space," she says. "How can I describe my heartache to leave him behind as a prisoner over there?"
When asked if she had hope of seeing him released soon, she said: "That's really uncertain because as a family, we don't have any power to bring him home. We feel really helpless."
But she said her family had faith and hope that the US government would bring him home.
Known in North Korea as Pae Jun-ho, Mr Bae was arrested in November 2012 as he entered the north-eastern port city of Rason, a special economic zone near North Korea's border with China.
His trial and conviction came at a time of high tension between the US and North Korea, in the wake of the communist state's third nuclear test on 13 February.
Tensions have since eased somewhat. In August, North Korea issued and then revoked an invitation for US envoy Robert King to travel to Pyongyang to seek Mr Bae's release.
North Korea has arrested several US citizens in recent years, including journalists and Christians accused of proselytising.
They were released after visits to Pyongyang by high-profile officials, including former Presidents Bill Clinton and Jimmy Carter.
The US accuses North Korea of using detained citizens as bargaining chips.
Meanwhile, North Korea said on Thursday it would allow six detained South Koreans to return home on Friday.
The group will cross over at the truce village of Panmunjom, North Korea's Red Cross said in a statement.
The identities of the six are not clear, but it is possible four are are South Koreans that North Korea said it had detained for illegal entry in February 2010, officials said.