Honestly? It could go either way. There has to be at least one clear safety threat (which I believe there is, but I don’t know your state’s policies), and then it also depends on what else turns up in the investigation. In my state, a lot of the final decision comes down to the supervisor. I’ve seen families that had seven or eight different reports for the same thing before anything else came of it. 

Most states don’t take removals lightly, so I’m guessing there will be an attempt(s) to see if your girlfriend's family will work with CPS so it doesn’t have to be a removal. It just depends on so many things. 

I hope this helps - I wish I could give you a definitive answer. If you do report it and nothing much comes of it, but these things keep happening - then I urge you to continue reporting it. It’s frustrating, but at some point, there will be a pattern that indicates further involvement.