talexb,
I am not going to offer you advice but tell you a bit about myself. I did not receive direction from either of my parents who are divorced. I was and still am a strong headed person and getting me to do something that wasn't my idea (even if I thought it was a good one) wasn't likely to happen.

I barely graduated HS. This wasn't because I was "gifted but unchallenged". It was primarily because I had a philosophical disagreement with western society's stance on the education system. I asked my mother to drop out of HS in the middle of my senior year. She told me that I didn't have to go to college but that HS was non-negotiable. So I moved to my Dad's in the middle of my senior year as my only chance of success.

I had always been interested in computers and had a good deal of proficiency as well. I did a bit of freelance work in and after HS. I had several jobs after HS to include telemarketing (unsolicited credit card cold calls - lasted 3 days beyond the 2 week training period) and a $4.25/hour job as a retail clerk. I decided to move to Arizona from Maine by greyhound bus (4 days and 3 nights - not fun) because it was all I could afford and ended up having to borrow money to fly back a few weeks later because it didn't work out.

I have never matriculated into college but have had a great career over the last decade working in and for the government as an information technology specialist. Here's how I did it. I joined the Army a year and a half out of HS. The military provides opportunities that wouldn't otherwise exist. It opens your eyes to a much bigger world. It gives you experience that is uncommon to come by elsewhere. I will not say that the training is great primarily because I already had competency in my field and slacked off in class but that's not to say it wasn't great training either. Your first enlistment length is usually tied to your job (which the Army guarantees as part of your contract) but there are dozens of jobs to choose from and some have initial terms of 2 years.

In a nutshell, I found my way on my own. I did it without buying into our education system. I didn't do anything "productive" out of HS. I think I turned out ok.

If I were to offer advice, which I am not going to (as I have been in the parenting gig myself less than a year), I would say this:
We do not always get to see the fruits of our labor. Sometimes we plant seeds but do not get to be part of the harvest. The best that you can do is encourage and support and be there if he should fall. Try a few things and if they don't work don't be discouraged or disappointed. The things that truly matter in life are the people we love and our relationship with them. I think it is far better to have a loved one that comes over for dinner every Sunday and occassionally asks for help with the rent money then it is to have one that is highly succesful in whatever field but harbors resentment for the person that wouldn't let them fly on their own.