Schoolboy James Bailey, 13, was frustrated with his condition and sometimes did not take his insulin and failed to check his blood-sugar levels and urine as regularly as he should.
His elder brother Michael told the Rotherham hearing: “He was generally happy, it was just when he was with the other kids who were eating sweets. He found it difficult to cope with.”
James’s mother Samantha Revill found her son, who she thought had flu-like symptoms, dead in bed when she awoke and Michael could not revive his brother.
Pathologist Dr Mudher Al-Adnani gave the cause of his death as diabetic keto-acidosis due to insulin-dependent diabetes. He said the teenager had high levels of ketones which are poisonous and make the blood very acidic.
The inquest was told James had smashed testing kits in frustration and on the weekend he fell ill had no working kit at his home in Birks Holt Drive, Maltby, near Rotherham.
Mrs Revill, a single mother of five, said he had been diagnosed with diabetes at eight and was reviewed every three months at hospital and had his own diabetic nurse but would often miss appointments. He started with two insulin injections a day but as he got older used a carbohydrate count and injected whenever he ate.
His mother said he was reluctant to use a urine testing kit which tested for ketones and a blood-sugar monitor which he was supposed to use two or three times a day.
Mrs Revill said: “When he was at home he always had his insulin when he should have but I found out when he was out he wasn’t injecting when he should.”
James fell ill on Friday, December 17, 2010 having missed a hospital appointment a month previously. His mother thought he had flu but James refused a urine test and his monitor was broken.
His mother told the hearing: “He broke quite a few throwing them at the walls in temper. It was a reaction to not wanting to do the tests.”
Her son had taken his insulin over the weekend but on Monday, December 20 she woke up to find him cold in bed. She broke down in tears and said: “I could feel he wasn’t moving. I held him and he took his last breath.”
An ambulance was called but James was declared dead at Rotherham General Hospital.
James’s grandmother Angela Revill, of Ash Grove, Maltby, who regularly looked after the 13-year-old, said she had once found sweet wrappers in his bed and told the hearing he had struggled with not being able to do the same as his friends.
Police investigated but found no evidence of a lack of care by his mother, grandmother or the authorities.
Deputy coroner Fred Curtis recorded a verdict of natural causes.
He said his family were conscientious in caring for James. “Mrs Revill was a caring mum who did her best in difficult circumstances with a young man who displayed all the features of a headstrong teenager.”