Advice about mother ‘in law’

To start off, me and my sons father ARE NOT together anymore. He is a terrible drug addict who has always put drugs over me and the baby. And his mother has always put her son over the baby as well.

For example, he has been using again, its easy to tell just by looking at him, she didn’t tell me because she knows that if I know I will not take my baby around him. (He’s not on the birth certificate so there is no custody plan)

I feel as though if you are not putting my son first then you don’t need to be in his life at all. She feels she has done nothing wrong and keeps asking to see him as if its my responsibility to let her visit with him. I really just want to tell her basically what I just said ‘you dont put him first so you dont need to be in his life’ but I dont want her to turn around and tell my ex to get on the birth certificate so they can see him. Mind you he is 23, still living at home, still having his meals made, laundry done, and even being woken up in the morning by mommy. I dont really know what Im asking here but I just dont know what to do about her wanting to see him but not actually caring about him over her grown adult son