My boyfriends mom came around my child on drugs and I don't want her around my daughter.?

My boyfriend's mother has always had a problem with prescription pills, and has once or twice smoked crack and meth. The other day she gets out of jail for not paying child support, because once again her drugs came first, before her own kids; she comes over uninvited, speeding horribly off something and comes to be around my child. She then starts talking about all the prescription drugs she had just taken, in front of my younger brother and sister and how she fought the cops- like they need to hear stuff like that; so im pissed at this point. I told my boyfriend about it and he assures me he will "handle" it. A couple days later she calls, and I want my boyfriend to warn her that if she ever comes around here like that again I will call the cops and she won't be allowed here anymore- he didn't. I was then forced to tell her myself and she handled it like a child, calling me names, threatening to take ME to court, and she wont stop. My boyfriend ofcourse defended her and we comprimised on supervised visitations with her. That was done. The next day she texted and asked if my daughter took a certain kind of formula, and simply answered which kind she took then all of a sudden she lashes at me and thinks im lying to her because im "pissed off for no reason" It then turns into this hour long harrassment against me over text, calling me names and verbaly abussing me. My boyfriend finally stands up to her and she goes off on him, telling him to find a new mother if he's going to let me keep her away from our daughter. He then threatens her with a restraining order and she comes back with "idgaf, i dont see her anyways" How do I convince my boyfriend that my daughter doesnt need a grandmother like her?