No online course like that available. That method isn't going to work for him either even if it can be arranged.
It's the general Math 12 as specified by the ministry of education here...
http://www.bced.gov.bc.ca/irp/prmath1012.pdf (pdf)
Essentially,
arithmetic and geometric patterns & series
graphing and solving exponential, log and trig functions
trig identities
function transformation
statistics & probability
Is there a particular aspect he is struggling with? I think sometimes people over-generalize their difficulties with mathematics based on only a couple of actual difficult areas.
Does he have problems finding intersections on graphs?
Does he have trouble finding the patterns, or creating closed form equations to series?
Does he simply have trouble remembering the trig. identities, or is it more an issue of knowing when to invoke one?
Can he visualize the movement or transformation of a graph based on what is done to the equation? Again, is it a problem of not remembering the transformations, or not recognizing that a function transformation is a useful idea in a problem?
Does he have trouble remembering the definitions of mean, variance, etc? or does he have trouble actually calculating or estimating them?
If he is simply not willing to
remember the basics, no amount of practice
applying them will help.
If he has trouble with application, then I would suggest to have him
create problems. That way he understands things from the "other side." You could take turns creating and solving each other's problems. Playing stump-my-sister could be good motivation.
Also, creating ones own problems with an eye towards having the solutions be useful towards ones own interests is immensely motivating.
You say he likes computer modeling...you could talk to him about creating surfaces that look like particular things, and how function transformations apply to this as well. Want to make two peaks come closer together? How would you change the equation to do that?
If he's into card games, applying probability to this is motivating for most people.
If he notices cycles of any sort, you could show him how trigonometry applies to almost anything with a cyclical nature. A wheel that goes around, seasonal trends, the earths rotation, what ever else he can think of that is cyclical.
If he has a bank account, he can model how it would grow as a combination of geometric and arithmetic series under various conditions. He could then model what would be better or worse under various circumstances using graph intersections.
I think you get the idea.