Mother of child Martyr wished a different son had died

Mother of 15 year-old who died in suicide mission:
     "It was sad and joyous what happened to him, meaning, he always liked the Shahada (Martyrdom). All children at his age do. He always cared for me. I would have preferred that one of his other brothers would have attained Shahada instead of him, because he was the joy of my life."