"On the last day of his far too short life my son begged me not to let him die. No four-year-old should know about death," Katrina said today. "We begged for help, we are supposed to put our trust in doctors, we naively did, and now my only son is dead. I wouldn't wish this on my worst enemy. My son died in my arms." And paying tribute to little Sheldon, the heartbroken mum said: "He was so beautiful, blonde hair, big blue eyes and the most amazing smile. He was such a lovely little lad, we were all so close. He was so caring and had a love of animals."