Casey Thornhill, 21, who had been diagnosed with borderline personality disorder (BPD), died last Wednesday. Ms Thornhill, from Beighton, Sheffield, leaves behind a family, her boyfriend, and her three-year-old son Noah. Family friend Rachel Jackson has set up a memorial fund to help Noah which has already raised more than £17,500. Casey Thornhill (pictured with her three-year-old son Noah), 21, who had been diagnosed with borderline personality disorder (BPD), died last Wednesday Family friend Rachel Jackson paid tribute to the mother-of-one from Beighton, Sheffield, describing her as a 'lovely person, vibrant and full of life' Rachel said: 'She was a lovely person, vibrant and full of life. She had some really good friends and most of all she was a fantastic mum.