Can I be arrested for my kids not behaving?

I am living with my children at my moms house while I am trying to get on my feet. When they misbehave she screams that she is going to call the police "if I can't make them behave". What will the police do if she calls them? It is impossible for me to be everywhere at all times. I have a small baby and 2 preschool age daughters and a teenager. She yells at them and tells them to shut up. If I intervene she tries to start a fight with me. She also verbally abuses me and calls me "big mouth" and acts like she is going to run into me when I am walking through the house. Thank you!