Hans Christian Andersen did keep diaries that have been published, but the passage Jack reads in Drawn Away is entirely fictional. I am not aware of any evidence that Andersen’s story “The Little Match Girl” was inspired by a real event or person—though it does seem possible.
Type 1 diabetes is a lifelong disease that strikes children and youth and destroys the ability of their pancreases to make insulin. Before the discovery and development of injectable insulin in the early 1920s (by Frederick Banting, in Toronto, Canada), type 1 diabetes was a certain death sentence. Today we can treat the disease, but there is still no cure.
For those curious about Jack’s blood sugar, or blood glucose (BG), readings, the normal range is between 4 and 7 mmol/L (millimoles per liter). When it drops even a bit below 4, things can quickly become serious—that’s why Jack always carries some kind of sugar for treating a low. There’s a much greater range of high blood sugars than low. When the meter just reads HI, like Jack’s did, that indicates an extremely high BG of over 30. Even a very high BG is not an immediate emergency like a low is, but when it is prolonged or untreated, it can lead to coma and eventually death. The higher the BG, the sooner the situation becomes critical.
Canada, where Jack lives, uses a different system of blood-glucose measurement than the US, where the normal range is 72-126 mg/dL (milligrams per deciliter).