If she's not doing anything about her kids, it could very well be possible that she thinks it's normal and the same thing happened to her growing up. People who get abused can fall right into that lifestyle and do the same thing to other kids. It's like children who watch abuse growing up tend to be abusive when they become adults. It's well documented. If the grandma is pimping out her kids now, she was probably pimped out as a kid.