I'll try to update you with what I remember:
Sam, Dean and their Dad all live through the horrific accident from the season finale. The demon possessed truck driver confronts Sam immediately after the wreck and Sam can't shoot him because he tells Sam of some future plan for him and the "others like him" - whatever that means.
Dean is in a coma and the prognosis is not good. Dad is also admitted to the hospital, but his injuries are not as serious. He asks Sam to have their friend get the car before the police go through it and find all the weapons, especially the old Colt pistol. He also gives Sam a list of supplies he wants from the friend which annoys Sam - he thinks his Dad is more concerned about confronting the Demon than trying to help Dean recover.
Meanwhile, Dean is walking around the hospital and wondering why no one is responding to him when he speaks. He goes to his room and sees that he is all hooked up to machines and realizes what has happened. At the same time, he sees some sort of apparition which is killing people in the hospital and tries to stop it. He also sees Sam and tries to communicate with him since Sam is "sort of psychic" - with no luck. He sees a young woman running around the hospital trying to communicate as he was and they start talking. He tells her what is going on and tries to stop the deaths. He figures out that it is a Reaper killing the people in the hospital.
Sam and his Dad get in a big fight while Dean watches helplessly. He gets so mad that he knocks a glass off the table and Sam realizes Dean is with them. Sam buys a Spirit Board and starts trying to communicate with Dean - successfully. Dean tells him a Reaper is after him and others and Sam says he'll try to help. He goes to talk to his Dad and he's gone. Sam takes his notebook and starts reading about Reapers. While reading, he sees something and realizes why his Dad asked for the supplies. Sam starts trying to find his Dad.
The woman who was talking to Dean finds him and tries to talk him and says something which makes him realize SHE is the Reaper. She spends a lot of time trying to convince him that if he fights it he will turn into a spirit like the ones he has spent his life fighting while still remaining in a coma.
Dad is in the basement of the hospital working on some type of conjuring spell. Suddenly, a janitor shows up and tries to throw him out and Dad realizes HE is the demon. Dad says he wants to make a bargain for Deans life. He agrees to turn over the old Colt pistol and the last bullet. The demon says he wants more . . .
Upstairs the Reaper suddenly starts disintegrating and screaming in front of Dean. He is suddenly drawn back to his room where he awakens from his coma with Sam and Dad at his side. Dad sends Sam to get some coffee and leans over and whispers something into Dean's ear. When Sam is returning with Dad's coffee, he sees him unconscious on the floor of another room. Efforts are made to resusscitate him - to no avail.
I feel badly for Jeffrey Dean Morgan - first they kill him off on Grey's Anatomy, now this!
