Oh, so sorry!
Maybe she just needs to talk through it? (She said hopefully...)
I think it's natural to worry about a big decision like this. And I'm betting that you feel very insecure about the choice, too. (Could be wrong there, but I know I felt insecure when I made the off-beat choice to homeschool...So I'm going to work from that assumption--I'm I'm wrong, stop reading now! LOL!)
Insecurity makes it harder to be challenged in this way, I think, because people feel defensive when they're insecure about their choices. So can you address her worry without acknowledging that she seems to be second-guessing your decision? Just let that part of it go and let it be about her feelings?
After all, since it's your decision, it doesn't really matter in any significant way what she says, right? So if you can let it roll off you and not take it personally, then it's done. You don't really have to persuade her that you're right, strictly speaking.
I'm not saying that's easy or that this is what you want to have happen...but I also know that you can only control your own thoughts and actions, and if you don't feel that you have to try to change hers, then the situation can seem more manageable, less infuriating.
Maybe if you just let her vent, she can get past it.
I would recommend that you calmly remind her after she has gotten to vent her fears to her heart's content that it is important that she get onboard the train or get off the tracks! If she is undermining things--even without meaning to!--that could make your DS6 sabotage the situation out of some loyalty to her.
I'm sure she wants him to succeed, so I think she needs to get past her fears for his sake.
FWIW...
