Moms I need help I'm at a loss right now.. my mother in law watches my son while I work full time. I work from 7-3:30 4…

Moms I need help I'm at a loss right now.. my mother in law watches my son while I work full time. I work from 7-3:30 4 days a week. I pay her $400 a month. My son is 7 months now and he requires attention not just sit in front of a tv all day.. my mother in law drinks. Today I picked up my son and noticed she's been drinking.. I didn't say anything as I didn't want to deal with her. If we confront her when she drinks she's stubborn and it goes no where. My mother in law can be greedy. She calls my grandma today, who just got back from Florida for the winter, and tells my grandma drama. My grandma has money. My mother in law like to tell lies about me and start drama between my grandma and I. In the past I've deleted my grandmas number off her phone cause my grandma doesn't need my mother in laws stress. I talked to my fiancé outraged and told him everything that had happened today. He suggested for me to call my mother in laws husband and tell him to take care of it. I told him she has no business calling my grandma. I want my grandmas number deleted from her phone. Also that My grandma and I could tell she's been drinking. He said he'll take care of it. I don't know what to do. She's he cheapest daycare I can afford right now. I want my son to be safe and have interaction. Please help and give me some advice.