Hi Jackie,
A diet to lower cholesterol in children is very similar to that of an adult. Review the information at the link below to learn more about a diet a to lower cholesterol.
http://www.healthcentral.com/cholesterol/lifestyle.html?ic=4026
Pay particular attention to the information on saturated and trans fats, omega 3 fatty acids, and soluble fiber.
All the best,
Lisa Nelson RD
How to Lower Cholesterol in 8 Simple Steps