Hi there. I'm not sure how old your son is, but you could try contacting Big Brothers/Big Sisters to enroll him as a little. They operate local branches all over the U.S. I believe the criteria for boys is an absence of a male father-figure at home, but you may want to check with them for details.
I was a Big Sister in the program for years, mentoring a 10yr old girl. It was a unique and rewarding experience and would highly recommend the BBBS organization.
I did a search for national mentoring programs and Mentor (http://www.mentoring.org/about_mentor) seems like it fits your sons needs. I do not have the answers to your other questions, but I'm sure if you contact Mentor they will be able to provide you with the appropriate information.
Another good resource would be your city's website. On my city's website, they've included volunteer opportunities that list mentoring programs. They might have local organizations that provide mentoring/mentee opportunities.
I am a father of four, two boys, youngest is a boy of 15. I was raised the only son of a single mom.
I am an Attitude Engineer, Certified Leadership Coach and serve as a mentor in a public high school. In the school year 2012-2013 they used a nine month program from my book as a mentoring platform for all 2500 students.
I am considering offering the materials I have provided as an 18 month course 1-4 hours per month to groups of teens no larger than 25 at a time.
Do you think something like that would serve your needs??