Each person is different. Different outcomes, ages, physical conditions, health problems, and so on.
A very old and good friend was in a coma due to a terrible head-on collision with a truck (tires on his car blew out), and of course docs wanted to pull the plug. His estranged wife came 5000 miles to take care of him and advocate for him. She refused to sign the pull the plug papers. Instead sat by his bedside and prayed and read to him for weeks. They said “he’ll die anyway”, then “He’ll never wake up”, then when he woke up, “He’ll be a vegetable”.
He is now walking, talking, working around the property, thinking, taking care of family interests, etc. And, he and his wife are no longer estranged and he is changed for the better so much that he is actually thankful for the accident.
PS. Very sadly, the hospital gave him Hep C. But he was around 50 plus at the time, so hopefully it will not have time to manifest much if at all.