I know someone who used Switched on Schoolhouse quite successfully with a teen who was ADHD and ADD and heading for JD. The public school kicked him out he was so bad. This was not a Christian family but he really did turn around.
Switched on Schoolhouse is great they have really improved the software since I started using it. My daughter still uses it, my son however I have switched over to the Florida virtual school as it is free if you live in Florida as I do, and it has the added advantage that I am not the only one nagging him about completing his work in a timely manner he has a teacher assigned for each subject to bug him about his pace chart. I know very well his procrastinating tendencies since they come from me. He is borderline adhd as well and they seem not to do well in a very structured environment like school. Florida requires testing or other evaluation yearly and we have always tested and he does very well 90 th percentile or better on his tests.