It's very helpful to hear this. I knew I would need to "prove" to those in charge that ds was ready academically, but I had not considered the fact that they probably would like to avoid something that would cause a major change in the peer interaction. Do you have any advice for how to address this concern with them?

The challenge I'm facing now is that I can't do the academics better at home. For the past 2 years, ds has had to work through curricula independently. It's gone well, but I feel like I need to find an instructor he can talk with, especially as the difficulty increases. We're exploring co-ops, virtual classes, and private tutoring.