Mother Issues

Lindsay • Hello, everyone! I`m Lindsay, stay at home mom and wife and loving every second of it. Baby girl #2 due October 25th!
Recently, around the end of May, my mother moved in with my husband and I. We let her move in on with the rule that she didn't have to help with our mortgage or pay a "rent" but needed to help with bills that would be affected by her living there (electric, water, groceries, etc.) So far she hasn't helped with any bills and she eats all. of. the. groceries. All of them. As in there's no loaves of bread or butter, no peanut butter and jelly, no fruit, no milk. I'll buy food and go off with my husband and daughter for the weekend, come back on Sunday and everything is gone. He's at his breaking point with it, especially since she doesn't lift a finger to help. How do I talk to her about this? I'd hate to be like hey you eat way too much but I'm tired of our food disappearing and my husband having no food to take for lunch. during the work week.