First, how wonderful that this young man has benefited from the boarding school "intervention"! Hooray! So, what comes next?

In general, I typically advise parents to adopt a parenting approach that includes a combination of structure/limits with mounds of love and warm responsiveness. Essentially, I'm referring to firm and consistent rules and restrictions (and agreement among caregivers!) mixed with a generally warm and approachable stance. For example, with a 16 y.o., this means firm rules about use of the car (e.g., only borrow for travel to and from soccer practice), consistent consequences each time these rules are broken (e.g., no use of car for a week), BUT balanced with loving communication (e.g., What was great about today? What was hard about today?).

This approach to parenting is also known as an authoritative parenting style. Research shows that this style of parenting is beneficial for the multitude of families in terms of child and adolescent emotional and behavioral adjustment. Authoritative parenting spans children across age groups, but the exact approach should be adjusted for developmental appropriateness. Okay, we've just scratched the surface! Good luck!

Other opinions?

What a great to begin -- he is staying on course!! As a parent, it is very clear that you are proud of your son and his accomplishments. You may want to have him reflect on what mmade the difference in his life and how he made the changes happen. The next step would be to have him talk (and you listen) to what he plans to do in the coming year:
Example, On a scale of 1 to 10 (ten being the best), where are you now? Wow! What have you done to make this happen? Where would you like to be in the next three months? (on the scale of 1 to 10)

I work with The Association of Boarding Schools (TABS for short), a non-profit with more than 300 member schools in both North America and abroad. I read your question about keeping a 16-year-old moving in a positive direction and thought you might be interested in checking out TABS at www.boardingschools.com.

You mentioned that he turned around his behavior at boarding school. It seems like boarding school is a good environment for him and he should continue to study there. If for some reason he needs to change boarding schools, you may want to check out TABS.  One of the best ways to check out different boarding schools is to use TABS School Browser. You can enter the school name if you have a particular school in mind, or search by zip code, and even view an A-Z listing of nearly 300 member schools. Each school has its own page and profile with lots of key information, and you can request info from multiple schools at once. It’s quite the time-saver!

Also, the TABS Guided Search tool lets you refine your search even more. You can search by gender, specialty, grade levels, and location. You can even add more targeted criteria including courses, arts, and athletic interests. It’s perfect for those who know what they want—and helps those who don’t to figure it out.  

Check out both at http://www.boardingschools.com/find-a-school.aspx