Dominic,
Most teachers are not trained as professional counselors, thus legally can't 'counsel'. But sometimes we walk a fine line between providing counseling and classroom discipline. What I find can be helpful, is to do as you have indicated and ask to speak to the student after class for a few minutes in a manner that is as non confrontational as possible. Something like " Hey John, perhaps I can get your thoughts on something after class."
Let him do the talking, starting with you asking: "Any idea why I wanted to catch up with you?" Of course the hope is that the student kind of knows things are headed in the wrong direction and will bring it up without prodding.
And then something like "Thanks for sharing that. And yes, if you could work on that I am sure everyone would benefit. But also I need your help. You seem smart enough and there are students in the class that need some help, maybe not a lot, but just to get them past difficult concepts. Would you be willing to help someone who might be struggling?" (nevermind that 'John' is one of the ones who is struggling)
The hope is that the conversation turns from 'John' being a victimized struggling student to taking on the role of a mentor/helper. And of course, mentors need to set a good example. Mentors also get to see the class a little more from the perspective of the teacher. Instead of being the 'problem' he becomes a solution. Note: it is easy to see this as a form of manipulation, but it cannot be that. You would have to genuinely need the student's help for a specific situation. It has to be real. So, think that through before approaching him. You would probably also need to talk to a couple of students about having an in class mentor.
Hope that helps. And yes, we could speak sometime, though it might be good to get through the holidays first.
