Tutor/educator for high school student

I am looking for a teacher/tutor to assist my 16 year old son with high school work. It is necessary that most sessions be in person, but it does not need to be at my location. An on-line session once in a while would be ok. I am thinking the position would require 4 hours per day, 5 days per week, but will consider fewer hours and more than one tutor. He needs help in math, language arts, science and history.