Even though he is just 12, specks of grey are visible in Siu Yau-wai's shaved hair. "Do you want to know why I have white hair? I have stress. I don't have an ID card, grandma," the boy once told Chow Siu-shuen, who brought her grandson across the border on false documents when he was three. For almost a decade, the outside world was alien and dangerous for Yau-wai, whose life in hiding was revealed yesterday when his grandmother came forward to the authorities and he received temporary papers. Chubby and sporting a wide-eyed grin, the shy boy lived in constant fear his next step would mean separation from his grandmother or, even worse, her arrest. Without any documentation or even a birth certificate, dodging police and staying under the radar was part of everyday life. According to Chow, the boy's parents decided he was a "bad omen" after his mother was diagnosed with breast cancer and his father lost an arm in an industrial accident. They abandoned him in a "paper box" on the mainland shortly after birth and their whereabouts is unknown. Chow, a Hong Kong resident, took the boy into her care and, when he was three, brought him to the city using another child's name and a two-way permit, which allows only for a short stay. WATCH: 12-year-old undocumented boy obtains temporary permit in Hong Kong Much of his childhood has been spent in a small public flat at Kwun Tong's Shun Lee Estate with his grandmother, 67 and grandfather, 80. He would only go out to play on Saturdays. Afraid as they were to go out, they were even more afraid to let people in. A visit by Housing Authority or census staff usually meant a secretive escape down the back stairwell to the park below, Chow said. Yau-wai loved books but would only go to the library "late at night" to avoid crowds. Borrowing a book was out of the question as he did not have an identity card. Seeing a doctor was impossible for the same reason. "When he was sick or feverish I would sometimes give him herbal tea and cooling patches," Chow said. "Sometimes I would have to take him to a Chinese medicine practitioner as they usually don't need ID cards." The boy said he had friends but none knew he was not at school. Neither did the family's neighbours know. He received a "home education", and said writing was his favourite activity. Chow bought books for her grandson, which kept him occupied all day as she worked as a car park security guard for HK$5,300 a month. She retired in 2012 and now lives on old-age allowances. With his prospects looking up, Yau-wai said his dream was to go to school and become an accountant. "I like to calculate." At a visit to a Wong Tai Sin primary school yesterday, he was found to have the education level of a Primary Three pupil, about four years younger than him. "His ability to answer Chinese and maths questions was pretty good. His grandmother has taught him very well," said Debe Yuen Poon Suk-han, principal of the Confucian Tai Shing Primary School, after interviewing him. Yuen said the school would consider accepting him if the Education Bureau would allow it. An Immigration Department spokesman said that if no decision was made on repatriation in the short-term, it would contact the bureau and discuss educational arrangements for the boy. The bureau stressed that all school-age children must have right of abode or a valid document issued by immigration to receive an education in Hong Kong. In the case of Siu, schooling arrangements would be made for him, based on his area of residence and level of learning, if het met the criteria. "I want to go to school. I want to work and take care of grandma and grandpa," Yau-wai said.