I am also in high school and also have the block schedule. I had a friend last year who skipped to go hunting in Wisconsin, and the teacher didn't appriciate it when she found out he was missing school to hunt. He should be able to get all of his homework in advance before you go so that may help, but if you do decide to let him skip I would say you are taking a "family vacation" to Disney Wordl or somewhere. Overall I would say let him go I think you would be making a safe choice!