He's come to tears several times over unschooling and wishes we were back doing school. He likes a measurable goal that he can tick off. But when I suggested returning to a course of study for him, he resists since he's not sure it will feel "real" if he's the only one doing it.
Maybe try to help him separate the aspects of what he enjoys from how he wants to get it. Obviously it wouldn't be fair for the whole family to stop doing what they're enjoying and go back to what they were doing before so that he can get what he wants.
Perhaps what he likes is the predictability of the day and the clear goals to reach. It's very satisfying knowing there's a goal to reach and a time limit and then accomplishing that.
But he hasn't had the experience of setting his own goals and reaching them. It's going to feel initially unsatisfying knowing that he doesn't have to reach a goal. That he can drop it at any time. That no one will punish him if he doesn't do something. That he can set the bar so low that he could reach it with his eyes closed.
And he's probably going to think in terms of school-like goals: completing a chapter by the end of the week, answering all the questions at the end of the chapter. Those are all arbitrary goals so they've needed someone to assign them and enforce them in the past in order to make them "real".
So what he needs are real goals for real personally meaningful reasons. He's stuck, a lot like kids who have been working to achieve As and Bs. If the As and Bs are taken away, then what's the purpose of working they wonder?
So maybe talk to him about personal goals. He does need time to deschool so he can come to value personal goals more than artificial arbitrary ones. The summer should help. So maybe talk to him about summer-type things he'd like to accomplish like learning to swim better or a family bike trip to the top of a local mountain or finding a great book series or watching all the James Bond movies in chronological order.
And as for predictable days, perhaps you could write the day's schedule down for him so he knows what's happening that day. (Be sure to schedule in "recess' so that you have the freedom to do something that isn't scheduled! :-)
Another one worried that she only cared about her friendships and was disappointed in herself to find that she isn't getting hooked on any "interests."
This is again about deschooling. Kids get convinced that school is the only way to learn just as fully as adults do. We assume that kids will embrace freedom as soon as they're given it, but they get brainwashed by the system too. They can end up feeling like textbooks or workbooks are "real" learning and doing something for fun is "just" play.
It would help to acknowledge her feelings. You've changed the rules on her and she was attached to the old rules. Maybe share that you're sorry that you didn't find unschooling earlier because it isn't fair that she has to learn to revalue her interests. She should have been naturally valuing them all along.
And talk about how it's natural for teens to value friendships. It's part of the process of being a teen and the journey to adulthood. She needs that part of the journey.
Perhaps it would help if she wrote down what she's doing so she can see all the things she is accomplishing.