Yes it’s counter intuitive. And it takes a few days to burn off stored glycogen so you would not be in ketosis for half the keto week. You would just be in limbo.
Cycling between carbs/keto may work best for her, but the keto doctors and scientists who are experts in ketosis don’t recommend that.
They say if you are allergic to nuts, would you eat them every other week? If you are lactose intolerant would you drink milk every other week? Would a coeliac eat wheat, at all?
If you are carbohydrate intolerant should you overdoes on insulin every other week?
I someone did 11 months keto and 1 month carbs then maybe