Okay, listening to this closly, there are several clues here.
Something tells me, while the mother does react overboard, the kid isn't blameless here.
The kid at first keeps telling her, "ask nicely, ask nicely." She responds that she already came in 10 minutes ago and asked nice and isn't going to ask nicely anymore cause he keeps playing head games.
Basically, I think the kid knows the mother has a short temper and knows what buttons to press. I know EXACTLY the buttons to press on any family member to get them riled up. There is a saying, we can hurt most the ones we love. Why? We know what sets them off. This kid is obviously provoking and antagonizing his mother. He's trying to play a control issue out with her and is using the tape as "proof" later on when he spouts of the child services crap.
She also threatens to send the kid to live with his Father, which he doesn't take to kindly to as a response by saying, "Now I'm not going to help you anymore." And proceeds to cuss her out and accuse her of not being nice as a reason.
Bottom line, the whole family needs to seek counciling to resolve issues if they are resolvable. The 16 year old is basically pushing the boundaries of control issue with his parents, what 16 year old doesn't tho, and his mother is fed up. He just happened to catch one time slice of a situation that has probably been going on for years.
The kid doesn't seem to be suffering for over abuse or neglect as, from the body parts I could see that passed in front of the camera, he did have his shirt off, there wasn't any visible markings or scarrings from trauma that way. He lives in a house, has his OWN electronics and dvds, tv, and chances are a ton more crap then I've ever had. He has money, a car, and may have been a bit spoiled in the past. That is just conjecture on my part about the spoiled but it would explain his reasoning for making this video with his mother cussing him out.
Now the mother isn't miss perfect mother either. She has made plenty of mistakes it seems and now has no idea how to solve her relationship with her son and chances are, there may not be an immediate solution until the kid moves out on his own and time passes. Even then, that's no garauntee but it sure does change perceptions for both parents and kids once they leave the house.