Although your W is probably not rational, there may be some very small nuggets of useful advice in what she is saying. I agree there does not seem to be a need for MC while your W is in the midst of an A. However, there may be a benefit to counseling for your children or family counseling. I am no expert, and I have not yet reached this point, but a family counselor or child psychologist may have practical advice of how to break the news to the children and how to co-parent. Perhaps this is what your W - in a brief moment of clarity - is trying to articulate.
I think the moratorium on MC while W is in full WAW mode does not necessarily apply to therapies that will help your children in the long run. You could consider calling a child psychologist or family therapist - you don't need your Ws consent or input for this - and ask to meet one-on-one to see what your options are.
