CHOW Yeung Oi-lai has only eight days left to bury her Hong Kong husband and return to her native Haifeng, Guangdong, with her three China-born children. But she is pleading to be allowed to stay in Hong Kong to look after her youngest child, three-year-old daughter Kai-yin, who was born here. Mrs Chow rushed to Hong Kong a week ago when she heard that her watchman husband of 13 years, Chow Hung-yu, had died suddenly on August 27, in an apparent reaction to some medication. Mrs Chow wants to be allowed to stay here in her husband's public housing flat with all four of her children. She said there was no one in Hong Kong to care for Kai-yin. Hong Kong also offered her children the chance of better education, earnings, and social welfare than China, she said. Yun Shat-man, chairman of the Hong Kong and China Non-Permit Mothers for Settle-Down Association, which has taken up the Chow's case, said the Director of Immigration, Laurence Leung Ming-yin, and the Secretary for Security, Alistair Asprey, were the ''number one enemies'' to thousands of split families. ''They execute the [visa] policy very cruelly,'' he said.