Disengagment - a matter of choice

Today, I was nearly jumping up and down in frustration over a child who apparently shows no interest in his work at all. You see, most of the time, if I scold the students, some will either show me a sulky response, or some form of mortification. But with this one - blase, nonchalance and absolutely-I-don't-give-a-damn demeanour irks me to no end. It is insolence at its utmost -

I have tried the soft approach - it did not work. I tried the hard approach. It still does not work. Words have the same effect on him as water has on a duck's back.  Nothing gets to him.
So now what?
The best description for this child is 'disengaged' - he is totally not connected to anyone nor anything.
It seems as though he lives in a world of his own creation- cut off from the rest of the world.  To him, whatever goes around him that is not synchronised with his own agenda, is something of an inconvenience to his life.  He is tactless to the point of being selfishly heartless. And what is worse, he does not even care that no one in the class likes him, or even bother about him.

How does a child ever reach to a point like that?
I have always believed that everyone has a redeeming quality...but so far...sigh
I end up huffing and puffing till I turn blue!

He doesn't care, or is it that he does not know how to?
He does not feel, or is he afraid to feel?
He is not connected, or has someone rejected him in the past to make him this way?

I don't know.
But he has chosen....not to care, or feel, or think.
And this is so sad.