Has he taken a "Safe Sitter" class? Along with training they help sitters learn how to set their rates and parents are confident knowing they have a trained sitter working for them. Once he completes the training (usually on a weekend) he can show his certificate and command a justified higher rate.
Safe Sitter® was founded in 1980 by Indianapolis pediatrician, Dr. Patricia A. Keener, after a colleague's 18-month-old choked to death while under an adult sitter's care. Dr. Keener developed Safe Sitter® as a medically accurate instructional program designed for young adolescents 11 to 13 years of age. Dr. Keener updates the curriculum regularly.
The curriculum is presented in modules which may be combined and are taught as one of two course options:
Safe Sitter® Basic is a 6 ½-hour essential curriculum designed for busy schedules. It includes Babysitting as a Business, Success on the Job, Child Care Essentials, Safety for the Sitter, Injury Management, Preventing Problem Behavior, Care of Choking Infant, and Care of Choking Child. It introduces Preventing Injuries and Behavior Management.
Safe Sitter® is a 12 ½-hour expanded curriculum designed for comprehensive coverage. It includes all topics covered in Safe Sitter® Basic plus Infant and Child CPR, Toddler/Preschool Guest, more in-class practice time and expanded information on Preventing Injuries and Behavior Management. (My daughter took this class at your son's age and it was invaluable, she taught me things I didn't know!)
http://www.safesitter.org/ ~ there's help on the site to assist you in locating a class, and there are scholarships available if one can't afford it, my daughter's best friend was able to take the class this way ✿