Tell me about comas (yes, I mean comas, not commas). What is the difference between someone waking up from a coma after, let's say, a couple of days and someone waking up after years in a coma? I started a story about a man waking up after ten years in a coma but then I got stuck. Do things like hair and fingernails/toenails keep growing? What about nourishment? Would he be constantly on IV (?)? Would he recognize his family when he wakes up, i.e. little kids would be teens when he awakens?
Thank you for the help.
So, I used to do this for a living. I tried to break down your answers into a few categories.
Memory: This entirely depends on the mechanics of the energy, ie what kind of brain injury did he suffer? Honestly, anything short of total amnesia is believable. What happens most of the time is that people do not remember the accident that caused the injury, but otherwise their minds are intact. Mostly, for people who get close to a 100 percent recovery broke in two directions. (No one gets a 100 percent recovery, but 95 percent is pretty damn good.) Some people, the minority, remembered everything up to a specific point, usually a few hours before the accident. The majority of people didn't have a firm time of what was the last thing they remembered before the accident, which is to be expected. Retrograde amnesia is super common, and a lot of times it will take anywhere between an hour to twenty four hours before the event.
Nourishment: We use Percutaneous Edoscopic Gastrostomy Tubes, almost universally known as PEG tubes in medical parlance, to feed our long-term coma patients. They're tubes that doctors place in the stomach There's dozens, a hundred maybe, of different tube feeding formulas that we use for people who can't eat for various reasons. The formulas are basically liquid nutrition that provides the calories a body needs. In a hospital they'd have an IV, but we removed them before sending them to a Skilled Nursing Facility.
Activities of Daily Living: Yes, hair, fingernails still grow while you're in a coma. Men will still have erections. Your body continues to function, it's just that no one is running the ship. The patient care techs and the nurses take care of all of the ADLs. They bath the patient, clean them up after they void or move their bowels, feed them, cut their hair and trim their finger nails. Good facilities will shower their patients once a day in addition to cleaning up after BMs and urination.
Waking up: So, I'm going to try and keep this short, but you don't just "Wake Up" from a coma. I used to work at world-leading brain injury rehab and we never had a patient just wake up have full control of their body. That is nothing short of a miracle, but it's super common in fiction. Any significant brain injury requires weeks of intensive therapy and then life-long efforts to overcome.
If you've ever partially woken up from a deep sleep or an intense dream those ten seconds of confusion and lack of mental facilities is the closest analog I can think of for waking up for a coma, only instead of lasting a few seconds it can last for weeks, or more. There's also associated motor neuron damage not to mention muscle and bone atrophy. For the most part brain injury rehab is two steps forward, one step back, and a half a step sideways. It's never like it is in fiction. The only thing I've seen in fiction that got it right was House of Cards, which honestly shocked the crap out of me when I saw that.
While I was doing brain rehab I had a few miracle boys, and I say that because they were all young boys. Guys who came back from full out comas and got as close as possible to a 100 percent recovery. They all had long fights back to health, and I think all would say that four-five years out they still have repercussions from their coma.
If you're interested in doing this realistically I'd strongly recommend that you look up the Rancho el Migo Coma scale. There are a lot of resources tied around that. In my experience everyone who was in a coma went through the levels described in that scale, although at different speeds.
Family: Yes, people remember their family, even before they can really process anything else. They might not be able to respond but they will recognize their family. If a lot of time passes, it can be frustrating. If you remember your little brother as a 10-year-old and suddenly he's 20 with a goatee and Viking hair, it might not be instant, and would probably take some time to process. The parents though, yeah, always. I honestly think there's some sort of bond between a loving parent and their child that transcends what we understand by science.