THE eldest son of a wealthy businessman told the High Court it was because his father ''was mental'' that he suddenly signed a $24 million gift of a commercial property over to one of his sisters. Mr Peter Chan said he would not have minded if the property at Marble Road, North Point, was given to a stranger or to charity while his father was in a normal state of mind. ''We would not have cared or minded then,'' said Mr Chan who denied he had wanted the property and had had numerous rows with his father about it. ''I never argued with my father ever. I love him,'' said Mr Chan, testifying before Mr Justice Jones. His father, Mr Chan Man-yee, 81, who had signed a deed of gift giving the property to his fifth daughter, Ms Chan Wai-chun, is asking the High Court to declare it void. It is the plaintiff's case that he was induced to sign over the property by Wai-chun, 43, by some form of trickery and fraud. It is also claimed that he is suffering from senile dementia. The family is split over the issue with the defendant and the youngest son and daughter, Arthur and Sylvia, in one camp, and Peter and the rest of the family in another. Mr Peter Chan who served with the Royal Navy in Portsmouth, England, returned to Hongkong in 1969 and started a travel company. In 1984, he left for Australia and lived off the rent from a property here that his parents had gifted to him. In 1989 his mother died leaving nine children. Worried their father might marry his mistress the family sent him to visit Peter in Australia. He denied they had numerous rows over the property, with him asking that it be given to him. ''That is absolute nonsense,'' he told counsel for the defendant, Mr Edward Chan QC, leading Mr Martin Liao. When it was suggested that his father did not attend his wedding in Australia because of the constant rows over the property, Mr Peter Chan said it was untrue. He said that if his sister Sylvia, who had accompanied their father on holiday, did not bring him to the wedding there was nothing he could do. ''I cannot have a conversation with my father and tell him to come because he is mental and would not know what I'm talking about,'' he said. When the witness returned to Hongkong in June 1990, he learned his father had signed the deed of gift while on holiday in Thailand giving it to Wai-chun. Questioned about the father's return to Hongkong from Thailand and being taken to Sylvia's flat in Sha Tin, the witness denied using physical violence to take away the father. He admitted telling his half-sister (his father's daughter from an earlier marriage) that the defendant obtained the property by cheating their father. But he disagreed that his half-sister told him to leave the defendant alone as it was their father's wish to gift the property to Wai-chun. The hearing continues.