It doesn't seem out of place to check in, ask how it's going, ask if any fine-tuning is necessary.
I could be wrong, but I'd suspect that the teacher might be realizing that a child who tests out of EVERYTHING is perhaps not well placed, and that her job will be easier if she isn't having to differentiate literally all of his work. That just doesn't make much sense.
However, if she gets him and wants him in class and he's generally doing okay, I don't think I'd go all in on advocacy either. Well, unless his behavior is worrying you, of course. But you say he seems happy. That hasn't always been true, so I think I'd hesitate to push too hard. Maybe soon, but not yet. I'd be dipping a tentative toe in.
All IMHO, of course...
