What do you call it when someone dying falls into a coma like state?

Comatose : The terms stupor, lethargy, and obtundation refer to states between alertness and coma. These terms usually require additional quantifiers when used in medicine. Akinetic mutism & locked-in-syndrome can mimic coma in a patient with certain grave conditions. A dying patient falling into a coma like state can also mean death.

Coma: Generally, coma is commonly a result of trauma, bleeding and/or swelling affecting the brain. Inadequate oxygen or blood sugar (glucose) and various poisons can also directly injure the brain to cause coma. Brain inflammation and infection are also causes of altered mental status and coma.