I don’t understand why the therapist has even revealed this stuff to a client (daughter shacked up (?), lives out-of-state, preemie, even the number of weeks premature). Or why she starts speculating (again, to a client who might be expected to have some kind of emotional reaction at the news) she might move when it’s a) not certain, and b) 6-12 months away. And then isn’t able to handle said expected reaction.

I don’t think you should have said what you said, but I don’t think she should have created the situation either. I would try to fix it if I had found this woman useful otherwise, but I strongly suspect that part of fixing it for her will be tackling what you said and why you reacted as you did with an attack on her family. If you’re not willing to address that, it might be a non-starter. I’d also be prepared for no apology at all from her.