Sorry that I can’t give you any sound advice as I am not an insulin user but my insticts are the same as yours. An improvement (or lessening deterioration) of kidney function, good bg levels, weight loss and using a little less insulin - it all sounds good to me whereas numbers to aim for being a ten does indeed sound counter intuitive. Having said this, it is best to get the views of those T2s who use insulin.
I’m sorry to hear that the DNs advice has upset the lady, this is unprofessional and shouldn’t happen. Try to accompany her to future appointments. Best wishes.