The father of the two boys rescued from a Quarry Bay nullah yesterday praised the man who drowned trying to save them. Sze Nang-ban expressed gratitude to 51-year-old plumber Lee Ying-kwong. 'I would like to thank Mr Lee for sacrificing himself to save my sons,' said Mr Sze. Lee, missing since Tuesday, looks set to be posthumously awarded a top bravery honour. Firemen yesterday called off the search for Lee, who was swept away while trying to rescue Sze Kin-man, 12, from a nullah behind Mount Parker Lodge on Tuesday afternoon. He had already saved Kin-keung, nine. Kin-man remained in critical condition in Eastern Hospital's intensive care unit last night. Dr Aaron Yu Chak-man said the boy, who was underwater for at least 15 minutes, was expected to be unconscious for a long time. Kin-man had pneumonia and damage to his brain and respiratory, circulatory and digestive systems. 'It is difficult to say that he will be able to make a full recovery,' Dr Yu said. He said the younger brother was in a stable condition but still in a state of shock. He would be offered counselling. Chief Executive Tung Chee-hwa, who will have the final say on the annual bravery awards list, praised Lee's actions. 'We saw people risking their own lives to save others who may not be even related in any way to themselves,' he said. 'I was deeply touched.' A government spokesman said: 'Mr Lee definitely merits consideration for the honour. What could be braver?' A list of bravery medal winners will be announced early next month.