She thinks he is her baby !

First let me give you a little back ground I’m 24 her son is 21 she hated that I had a house and my life together and when he moved in she cried and begged him to come home for a week when we got engaged a year latter she flipped when we told her we were ttc she stopped talking to him for like 3 weeks and told him we need to Waite mind you we were married already ,it took 2 years and 6 fertility treatments to conceive when we told her she was PISSED she came to no sonograms I had 2 a week because I had a high risk pregnancy . But now she had him a whole bed room at her house decked out crib toys bottles but gave us nothing not one thing at any baby shower after he was born she would walk in and rip him from my arms or anyone who is holding him and now she demands we use the bottles she wonts us to, will take away his toys and make him hold stuff she brought him to play with, Will refuse to feed him when I fix a bottle because “ he isn’t hungry “ when he clearly is ! when we go out in public she takes the buggy from me and pushes it when people say he is cute and ask how old before I can open my mouth she is staying thank you he is 3 months like BITCH he is my baby not yours !