MIL problems

My MIL is horrible with money. Currently, she is waiting for her van to be repossessed and plans on filing for bankruptcy next year. She asked to stay with us to "get away from the stress" i.e. she needed us to support her. We agreed because we knew she would help us around the house and could watch the kids every now and then. We asked for her to help us with groceries once in a while especially since my stepson was coming to live with us too. She agreed. It's been over a month and she has not helped us out financially. No. She keeps asking us for money to buy cigarettes and soda. We did the first few times as a trade off for watching the kids. Now, we are tight on money until next payday. The last pack we bought her, we explicitly told her we could not continue to fund her habit. Especially since she is asking is every two days. She will pout and basically throw a hissy fit when we won't buy them. She says we will be responsible for her acting like a bitch because we did not buy her cigarettes or she will stop helping around the house. We are getting more and more frustrated. Let's top it off that she tells us her ex-daughter-in-law will take care of her when she gets older. Ha! She won't even go and check up on her husband who is now starving at home because they have no money. My husband's ex used to help with my MIL groceries because she watched the kids a lot. Now that she doesn't, she stopped doing it. When my MIL tried asking her ex-DIL for a favor, she "joked" that she wasn't blood family and did not have to do anything for her. Please tell me why you think she will take care of you. Also, my MIL had a job lined up before coming to stay with us. That would have solved more problems than coming to stay with us. She turned it down and said it was a "family emergency". The one who hired her said she could still work in our state but my MIL said she forgot the headset required to work from home. I told her that can easily be mailed and at least she would have another steady income coming in. She just brushed it off.

Sorry for the long post. I'm 5 weeks pregnant, lacking sleep and my usual caffeine and just generally tired. She is frustrating me and I have half a mind to tell her she can just go home and let her favorite DIL take care of her.