While doing some research, I came across a class on Coursera, covering World History Modern Times, and it is a college level course. You can purchase the certificate course, but I am not sure if they are eligible for actual college credits, like taking the CLEP would be. We will be doing the free version, both parts, or he will, I don't think I will do it as my daughter needs me to concentrate on her too. Check out Coursera if you are having a hard time finding affordable resources for High School level classes.
As a hands on activity, I will be having him create a timeline of World History. I might let him do it on his blog, as he has not had time to blog in a real long time.