I am concerned about "well below 20 g of carbs per day".

This is too low, and as someone else mentioned, it could cause the body to become very unwilling to burn it's supplies, especially if it is used to a high carb intake previously.

If she adjusts to following Induction *precisely* and exercising, and still doesn't see loss or sees gain, I would suggest maybe trying the Atkins Fat Fast (see link)

http://atkins.com/Archive/2001/12/21-237659.html

HTH