Overbearing mother-in-law

This is gonna be a long one guys, im sorry! My SO's mom is driving me absolutely bonkers. She babysits my kids(from a previous relationship) in the mornings to get them to school, and because she doesn't drive she waits at my house all day till we get home. It helps her because she has no income. She cleans, which I do appreciate... but she does a little much. And my house is nowhere near dirty by any means mind you.... she goes through my boxes in the basement, and takes it upon herself to take things that she needs. She rearranges our bedroom, clothes, me kids walk in on her going through drawers in our bedroom. When I get home she points things out to make it feel like she wants me to feel like I'm not doing enough around my house, and that she has to do it. After taking her back home she then proceeds to call him 4-5 times a night to ask him things like, what are you eating... what time are you going to bed, etc. After i pay her every friday, she then guilts him into giving her money to go gamble or anything she can come up with. She is involved in every decision, every argument... im suprised she isnt involved in our sex life at this point. And finally, at least once a month he will get a call or text asking him to talk me into letting her move in with us. he knows my frustrations, but he never says anything to her. i dont want to feel like im nagging or nitpicking, but at some point i want her to ler him go. Its hard to have a life and a family with a man who is baby-ing his mother. Am i asking too much? What do I do? I feel like I am forcing myself to even be polite to her anymore because I am so frustrated with her, and I don't want it to be like that. Please help. 😞