I've tried several forums including IMDB and NameThatMovie.org looking for this title, but with no luck.
I belive it was a movie (Or possibly a show. Don't remember.) I saw it on TV over 12 years ago, but it was probably made even earlier. This is what I remember:
These group of teens accidentally hit this other teen boy in the middle of the road at night. The teens get out to see if hes okay. Oddly enough, the boy doesn't appear to have suffered any physical injuries abd is able to get back to his feet, which shocks them. However, he does seem rather catatonic, zombified and seems to have underwent some sort of personality change/ amnesia as a result of the collision. The teens ask him if he's okay and explain to him that they just hit him with thier car and ask him if he needs any help.
The next scene I remember is that when the boy gets home, his father gets mad and starts yelling at him. He then smacks him in the face. Based on the fathers behavior and actions, this appeared to be a usual thing prior to the accident. But the boy responds in WTF type way and asks his father why he did it. The boy then hits his father back (at least I think so) and coldly threatens him, telling him something like: "If you ever him me again, I'll call the cops, tell the CPS, or whatever it is the kids are doing these days." I don't remember the line verbatim, but that's pretty much what he said. That fathers reaction was shocked and taken aback, like he couldn't believe his son actually stood up to him like that.
Ok, so... I know a movie with two very similar scenes to these ones, but not exactly...
The first one would be this (The clip from 1:16 ~ 1:30): -
And the second this: -
Now, the movie is not as old as you said it should be, nor the scenes happen precisely as you described. But it's so similar that i thought that it worth the try! :P Chronicle (2012) http://www.imdb.com/title/tt1706593/