Subdural hematoma-looking for some reassurance

I'm hoping that some of you experienced neuro nurses can give some information that may, or may not, reassure me. My boyfriend suffered a head injury on Nov. 17. It was missed when he was initially checked out. He is now being observed and is awaiting MRI tomorrow. His nurse practitioner has a strong suspicion that he has a subdural hematoma and will likely require surgery. Can anyone give me some input on his prognosis? What to expect during surgery? Risks? Possibility of some of his symptoms becoming permanent or additional issues related to surgery? Thank you so much for anything you can offer. I've been out of nursing for about a year and a half but my experience was in psych and family practice so neuro isn't exactly my strong point.