If you want to use the science that Lie to Me is based off (which does exist), you can see a microexpression of a smile at 2:29 when he is talking about how Casey was bullying him.
Also, at 3:26, when asked if he might have an anger problem, he just smiles and almost laughs. What kind of kid does that?
And at 5:50 when he is asked if he is sorry, and he blatantly says no, but then corrects the answer to yes after receiving coaching from his father...shows that not only is he not sorry for any of this, but that he most likely has been coached on this interview and knows he is supposed to give the "right" answers.
And one of the worst moments is at 6:35 when he is asked to empathize with Casey, asking if he thought Casey might have been upset, sad, scared, and worried. This kid just smiles and laughs when he is supposed to feel/understand the pain Casey has gone through.
And even in the end, he apologizes for picking on him.
Don't really feel sorry for this kid. From watching the interview, I feel like he almost enjoys this attention. Wouldn't surprise me at all...