My 13 year old son wants to be a pediatrician, what are ways to get a early grasp about the job?

Work at MD office. Volunteer work at community center rather than hospital. Talk to his doctor . Maybe he can shadow him for a day.
Volunteer and Shadow. In memphis, we are fortunate to have both st.Jude's childrens research and lebonheur childrens hospitals....Have your son do a bit of on-line research and then make himself available in a community pediatricians office or volunteer his time in a similar childrens hospital. He will be able to gauge his interest in taking care of ill children. Also, many mission opportunities that focus on kids.