I hate to say it but I'm really not surprised at the result. You did what you could, you can at least tell yourself that. And what the other poster said about how if someone else makes an accusation against them it will be taken more seriously is also true. However, unfortunately, CPS can't really do much unless more than one person comes forward about child abuse accusations or there's serious injury or pictures/video of the abuse taking place.

You still did a good thing for your nephew.