Good luck on the meeting. I know that even if you are aware that Dr. C is there to protect the interests of your S, the personal stakes are so high for you that it is very normal to be anxious. This will be expected, & not read as something to be concerned with. If anything it shows how worried about your S you are. If H meets w/ her it is all cool, rational argument, Dr is very likely to see this as not being focused on the interests of your S and worried about the outcome for S. That's part of the training & experience. So, relax and just allow yourself to be nervous (I know that sounds odd, but I mean just that - don't pile on your nervousness by being nervous about how you appear. You will appear like a concerned mom. That's in your favor.
On the earlier TM about H's lack of info on your dog, I don't see anything wrong with demanding that you be informed how your dog is doing. It is not about you or him, it is about a loved pet. You have every right to insist on good communication when it comes to your S and your pets (obviously the former is far more important). He is the one being unreasonable here. That said, try to think ahead and communicate your expectations to H so that he can meet them without feeling criticized when he doesn't do what you want but haven't made clear. This is especially true if this is a R pattern with the two of you. Work on changing that.
If there are ongoing problems w/ communication on S, then you present your concerns and ask him for what he thinks would be best to do to improve things for S's sake.
So, practice communicating expectations so that he has a chance to meet them, and then thank him for doing so, rather than expecting him to read your mind (he has shown he can't) and then criticize him (your TM was a very indirect & mild criticism, but what he heard was that he failed and was wrong, just saying). He needs help figuring out how to meet your needs and expectations, and then you can reinforce that with appreciation. A much healthier dynamic/pattern emerges.
Again, good luck on that meeting.
Me: 50 W:43 S6, S3 M: 12 yrs. T: 17 M is bad & Not happy Bomb Mar '14 S 5 Feb '15 D Bomb 13 Apr '15 (but "no hurry") DB Coach May '15 Wants proceed on D Aug '15 Starting 1-on-1 negotiations Sept '15