Me too. Don't be nervous, but in a meeting like this I would tend to want to get more info than I give. I like to know what I'm dealing with.
At this point I wouldn't defend his behaviour just reassure the director that you will be working with him on this.
Let the director talk and then give it time to digest, especially if she says anything that makes you feel defensive of you son. Better to be tight lipped, then gather your thoughts and schedule another meeting.

Good luck today.
p.s. don't be nervous, Kriston and I are big thinkers and super analyzers. I like to prepare for the worst and expect the best!