welcome & thank you for being so caring about your students.
conduct disorders is pretty much an umbrella term when used in the name of this board. it covers a lot of territory from adhd, bipolar, depression, anxiety,etc.
i have the same questions. i assume you've approached the parents. what's their take on this extreme reaction he has? have they considered an evaluation? have you referred him for a school based evaluation? is he, perchance, getting undue pressure at home to be the perfect student?
kris