You’re confusing ketosis with ketoacidosis.
Ketosis is not a pathological condition. It is simply using fat instead of sugar for energy metabolism.
Ketoacidosis is a complication of diabetes, which ironically, can be treated with a ketogenic diet.
The diet was originally developed to treat epilepsy.
https://www.epilepsy.com/learn/treating-seizures-and-epilepsy/dietary-therapies/ketogenic-diet
“Several studies have shown that the ketogenic diet does reduce or prevent seizures in many children whose seizures could not be controlled by medications.
Over half of children who go on the diet have at least a 50% reduction in the number of their seizures.
Some children, usually 10-15%, even become seizure-free.”