If you aren't already aware of them, there are some great resources here:
The Kahn Academy The Hippocampus Academic Earth The Annenberg Foundation Purdue Online Writing Lab (OWL) The OER Commons You might be especially interested in
this subset of the OER resources.
It would be easy to use these to set up a co-op high school. There is enough there to get you started and give you some resources to build from, and incorporating these kinds of online resources takes some of the pressure off of the parents to develop complete courses, and allows for more flexibility in scheduling, because students can access the bulk of the content instruction at their convenience. IRL or group online chat facilitated discussion sections once or twice a week in combination with a message board for discussion questions and sharing writing and projects would help round out the co-op experience.
