Nina Wang Kung Yu-sum could barely walk in the months before her death and had to be carried up stairs by a security guard at Chinachem Group headquarters, the late billionaire's estate trial heard yesterday. Wang had been unable to keep food down and her siblings were worried about leaving her alone at Chinachem's office in Tsim Sha Tsui East, where she also had living quarters, the late billionaire's younger sister Kung Yan-sum testified. Wang was often wheelchair-bound during October and November 2006, Ms Kung added. Wang died of cancer in April 2007. Jonathan Harris SC, barrister for fung shui master Tony Chan Chun-chuen who is a claimant of the estate, accused Ms Kung of exaggerating her sister's ill health. 'I suggest Mrs Wang was capable of looking after herself and that she was not as ill as you've been describing,' Mr Harris said, noting that the late billionaire had been healthy enough to attend a key meeting on October 16, 2006. 'She was very ill,' Ms Kung replied. 'I was very worried about her.' Wang's health and state of mind at the October meeting is crucial to the legal battle between Mr Chan and Chinachem Charitable Foundation over her HK$100 billion fortune. Wang signed a document at the October meeting, which lawyer Winfield Wong Wing-cheung has testified was a 'partial' will that left about HK$10 million - to a person with the surname Chan. Mr Chan's legal team has argued that Mr Wong and Chinachem sales executive Ng Shung-mo had actually witnessed a will that left their client in control of Wang's entire estate. A key issue in the case is whether Wang was healthy enough to void an earlier will that had left her fortune to the Chinachem foundation. Yesterday, Ms Kung said her sister's health went up and down daily, and that she had tried to hide the severity of her illness from Chinachem staff. Ms Kung agreed that her sister had been capable of making business decisions at the time, including leaving HK$30 million to the China Association of Social Workers. Mr Harris also questioned Ms Kung about a meeting with her siblings one day after Wang's death on April 3, 2007. The trio searched drawers in Wang's home to see if they could find any 'important papers', she told the Court of First Instance. Hours before the search, Wang's siblings had been called to a meeting with Mr Chan who said he had a document that he wanted to show them, the court heard. At that meeting, Mr Chan offered to give the siblings one of Wang's famous pigtails to be placed in her coffin before cremation, but he never did, Ms Kung said. Mr Chan whispered something in Wang's ear twice while she lay dead in a hospital bed, she said. Ms Kung denied suggestions that she had known details of Mr Chan's will before the search on April 4, 2007. His name was not mentioned during the search, she added. 'We were just trying to take a look in the drawers. But it also had a little something to do with Mr Chan ... We thought 'what else might be in her drawers?'' Mr Ng suggested that a lawyer be present at the search so he called on Mr Wong, who asked the siblings if they were looking for the partial will, Ms Kung said. Wang's sister learned that Mr Ng had previously mentioned the document to her brother, who dismissed it as a 'trivial amount', the court heard. Ms Kung said she first learned about Mr Chan's will during an April 7 meeting.