After decades of smoking, Kwok Shu-ming's lung disease became so bad that he was "imprisoned" at home for seven years, forced to give up his job and depend on his wife, their son and daughter, and an oxygen machine.
However, he has been given a second chance to live thanks to an organ donor, and he has seized the chance to fulfil a dream that grew over those years trapped in his home - to persuade people not to smoke.
It was last summer when a deceased donor gifted him the lung transplant that changed his life.
"It's been so long since I could go out and celebrate Chinese New Year. I haven't paid a New Year visit to my mother-in-law for 10 years and this year I could finally do it," said Kwok, 59.
"If you fall ill, it's your own problem, but you're affecting your loved ones too."
Kwok started smoking when he was eight. He went on to become a cross-border truck driver which meant he could smoke as he worked.
"I used to tell my wife, 'When I'm in my coffin, remember to put cigarettes in it too, or I'll come back and find you,'" he said.
His wife, Pang Kit-fan, 51, added: "When I asked him to quit, he would say, 'Why don't you try quitting dinner.' But he went on to suffer so much from smoking and regret it bitterly. He felt he was a burden to us."
He began to have difficulty breathing and in 2005 he was diagnosed with pulmonary edema, where fluid collects in the lungs, and bronchiectasis, where the airways get damaged.
For seven years, he was "imprisoned" at home. He suffered sleepless nights going over what he had done to himself and his family. Once, he nearly jumped to certain death from their tower block window in Tai Po, but thoughts of his daughter, who is still at school, stopped him.
Kwok was told he would not have much longer to live, but things changed when he was registered to wait for a lung transplant in 2011. Though he knew the chances were slim, it gave him and his family hope.
Then that slim chance materialised. "I really want to thank the donor's family though I don't know who they are," said Pang. "When I die, I am going to donate my organs, too. They will be of no use to me then but will be such a blessing to others."
Kwok was in an 11-day coma after the surgery. The day he woke up was his birthday.
"Before entering the surgery ward, I told myself I must come out. There are so many things that I still have to do," said Kwok.
"The thing which I want to do most is to persuade people not to smoke."
He recalled confronting a smoker in his housing estate. "I said, 'Sir, you can't smoke here,' and he ignored me."
Kwok lifted his shirt and showed him his scar. "I told him, 'If you don't want to be like me, please stop smoking.' I didn't want to pick a fight, but I felt I had to do my part in telling him."