You don’t need a coma for that – I manage it every day.
But if you lack my gifts, consider this :
https://www.flintrehab.com/coma-after-brain-injury/#post-coma
“Individuals with post-traumatic amnesia often struggle with memory, so they may not be able to recognize familiar faces and may appear confused or disoriented. However, individuals with post-traumatic amnesia should be responsive and able to demonstrate purposeful action.
Nearly every coma patient who reaches the state of post-traumatic amnesia will make a functional recovery. In fact, patients who transition from a coma to a minimally conscious state within 8 weeks are most likely to transition to post-traumatic amnesia and regain higher functions.”
Basically every coma is caused by some form of brain injury, but the degree of coma (as rated by the Glasgow Coma Scale) and length of unconsciousness are the key in determining recovery outcomes. So in your example it’s likely the patient would “wake up” as a child, with some limited chance of developing adult abilities & awareness.