My daughter is 19 with a four month old son. She lives with me and her father. We as grandparents take care of him mostly. My question is that how long does my daughter have to be gone in order for it to be considered abandonment. If she states that she will be home at a certain time and doesn't return at that time how long do I have before calling the police to file abandonment charges on her?

Sorry does not work like that, she is gone, in most states in the US, abandonment is where she lives child at walmart or somewhere and drives off.

She has provided for the child and the child safety by allowing you to watch her.

So she has done nothing criminal,

You can use this as a reason to file for custody or guardianship of the child in family court to attempt to take her rights away

But you call a family attorney and file in court not the police

I understand were you are coming from. My Daughter leaves her 4 year old twins with me and is gone for weeks. Won't answer her cell phone and I have no right to even get the medical attention if the were to need it. Grandparents have no rights. Need lawyers and fight in court. Then what happens You have to prove unfit parent.