I'm probably going to come across as a complete *** for this... but reading your post, in particular the following...
Screeling wrote:
He isn't what I would consider functionally literate.
Quote:
There is a good chance he will not graduate on time if this happens, which, pushes the chances higher that he will drop out and just get a G.E.D. The military is likely the career path he will choose regardless.
Lets say he manages to complete the work assignment... is doing so going to magically make him functionally literate in the next 3-4 weeks from his current level? Is he prepare to be a high school graduate over the course of the next year, since he appears to be a junior now? If he does graduate, mostly on the platform of your effort, is he prepared for anything academically beyond high school, or for any profession that requires more than manual labor?
Perhaps it would be best to work on the assumption he is going to fail this class, and put your well intended motivation into helping him with the recovery and demonstrating that a failure isn't an excuse to give up, but to dedicate and push harder? If he fails and decides to drop out, well, chance are enormous that without your help, he would have already failed, and he is no worse off, and no better off. If he fails and meets the challenge, turning around his attitude of academically lazy, then he might yet be better off for your effort.
Otherwise, its likely you are wasting your time, that would be better spent being a big brother to someone that honestly wants to succeed with the drive to do so, but needs the support to get there.