Is it fraud to recieve money from the state for children if they are in the care of another person?

In 2015 I received a 55.6 month presents it in. My mom was awarded temporary guardianship of my children. She receives $303 per kid per month I have three children. For the past couple months the children have had unsupervised overnight stays with myself. They have been with me at my house 24 seven since June. Even though they’re still legally in my mom‘s custody she is receiving the money and not helping support the children.