Replies to 'Lying about Money/Spending'

If you feel you have to get involved then choose your approach very carefully, keeping in mind it really is not any of your business.  May be  there is a reason to the deceit.  Avoidance, maybe you should give her a chance to explain and if you talk about it then maybe she will either try to change, tell him herself or just tell you to not say a word after she hits you with a baseball bat.  Just kidding, but money is a touchy subject.