What can be done??

I just found out my stepdaughter’s mother has been giving my stepdaughter, who is 7 years old, a controlled substance. It is not prescribed to my stepdaughter.. it’s her mom’s fiancé’s son’s medication for ADHD. It’s called dexmethylphenidate. My husband was at work and told me to go and file charges against her mother because it is illegal to give someone a controlled substance who it is not prescribed to. I have a recording of her mother admitting to it. Well, the cop isn’t gonna do anything until he talks to her mom first to get her side of the story. Which I believe is complete BULLSHIT! I have her admitting to it on audio and screenshots of her teacher telling me how she was behaving in school because of the medication and it’s ILLEGAL! He told me he was gonna tell her that she can’t be giving her medication like that when it’s not prescribed to her.. like this women is nuts and you think you telling her not to do something is gonna work?? Wtf is wrong with the world. It’s hard to do anything else because they’re in the middle of a custody battle and the attorney hasn’t returned our call yet. Cop said he would contact child services, but I’ve dealt with them dingbats before and they don’t do shit. Their findings of abuse and neglect are 50% or less. So we’re at a loss and our kid is just suffering through this bullshit.

Edit: my husband spoke with another officer and he said she’s allowed to give her kid whatever she wants because it’s her kid. My husband hung up on him.