How can i get temporary cust0dy of my great grand child. His parents keep leaving him all the time, weeks at a time. Don't call. We don't know where they are.

You can ask the parents to give you guardianship. You can consult with an Attorney and attempt to get legal custody without their consent.

If he is abused or neglected, then you owe it to the child to file a report with Child Protective Services to keep him safe.