I'm watching Clannad and Kanon (Two very great animes) and they include two people that have gotten into big accidents, causing them to go into a coma. But this is a health question, not anime.
For example, in Clannad, a girl was in a car accident and was in a coma, or sleep for 3+ years.
In Kanon, a girl fell off a tree and hit her head on one of the branches from about.. 13 feet? And slept for 7 years and woke up.
The animes have nothing to do with this question, but I'm wondering if it's