I don't think you can help this time, Rhapsody, and I can't see that child services or whoever are going to just let you take (hide?) the child? I imagine if the whole thing is a lie it will all get sorted or and/or child services will contact you (rather than a foster home necessarily, they have some trouble finding them and they cost money) when/if they're looking. I think your niece and her men will have to work at sorting this out themselves?

We can't do everything, even seemingly necessary things all the time. If you get sick(er) it will be a worse situation than it now is? You must think of yourself here so you can help sometime in the future if still necessary. This is a painful situation for all concerned but not an "impossible"/necessarily horrible one; special services isn't going to eat your grand-niece :-) at least not today?