They will probably keep him in the coma, whether it is medically induced or not, for a while.
Keeping the brain's activity levels low helps optimize and speed up healing.
It also makes it easier for them to take care of him and monitor him without risk of him hurting himself.
The catheter will help relieve the swelling, and they will be able to monitor the pressure in his brain (ICP or intracranial pressure). He probably rated low on the Glasgow scale, which means he had a pretty severe injury, especially if he was unable to regain consciousness.
I imagine they've done a decompressive craniectomy, which means they removed a piece of his skull to allow the brain to swell without becoming trapped against the skull itself.
If you get any word from the doctors on how he is doing, post it.
Right now it sounds like he will recover, but be warned, he will probably not be the same.
Depending on the side of his brain the injury was on, he could have lost some memory abilities, learning abilities, communication skills, etc. He may be a different person--brain injuries can change someone's personality.
Please keep us updated. I am not religious, but I'm hoping he's ok--the doctors know what they are doing.
I hope this helped.I want to be a nurse someday, so excuse any "doctor speak" i left in. :/