What would you do?

My stepdaughter has a history of stealing and dishonesty.She is 21. She had a baby last March. She is living with us.. I am unemployed due to physical limitations. She has not worked since Feb. She is in a relationship with the father of the baby and they are planning to move in together. She says that they both want to wait until she gets a job. Her boyfriend does not want her to go back to work at her previous job because of the hours. While she searches for a job she is here. We live in a rural area and jobs are few. She is getting WIC and foodstamps. We have used the foodstamps to buy groceries once but there was about $100.00.. I ask her today, after she had spent the weekend with her boyfriend (who has a good job) for the the food stamp card to buy a few things at the store. Not intending to use all of the money left. She said that she could not find it. She left. I looked in the top of her closet and it was there. I called the number and no money is left on the card.