Scary mother in law

I have struggled with my mother in law since I had my baby(she is 6 months). My mother in law watches her while I work. She always acts like she knows her better, like she knows what's the safest and best thing. She told me that my baby doesn't sleep in the pack n play(which I have used for months to let her nap in). She said it's too hard so she was going to buy an extra pad for it. I told her no that she shouldnt do that because its unsafe. She argued it was unsafe without it. I said it's a firm no. Well she did it anyway. Today I pick my baby up and she said baby slept well today. She told me I put her in the upstairs bedroom on a quilt on the floor with the door shut. I said well she needs to nap in a pack n play. She told me that she she wont move the pack n play upstairs because she uses it downstairs. Well she has two but says that the one is bad. I offered to give her mine she said no, I have enough stuff. So every time I tell her something I want done with my baby she ignores it and chooses a less safe option because she has 4 babies and she knows better. Well it's my baby not hers. I feel like my only way out is to quit working but I cant afford it. What do I do? She wont listen to me. And last time I told my husband he told her she had to do what I said she came down to my house and started yelling at me. So I feel like I have no voice. I want to cry because I'm so worried sick something will happen.

Edit- I dont want her on a blanket on the floor sleeping without someone watching because she rolls over and crawls in her sleep. She moves a lot in her sleep. The room isn't empty so she could easily hit into something and she could easily roll herself up in the blanket.