I am interested to know the son's perspective on all this?
What kind of say is he having in the planning of the ride? What kind experience does he have in cycling? In camping? In meeting other people? In adventure?
How active is he in other activities and sports? Is he going to be able to cope with not communicating through social networks for extended periods?
What kind of bicycle is it envisaged that he will do the trip on? Does his bicycle fit him? What is the current longest distance he has ever ridden?
Have you thoughts about letting him sign up as a member of BikeForums (the threshhold age is 13, IIRC).
I am holding my thoughts on the plan until the OP provides an insight to these questions.