Now I get where the other thread has spun from!
So, here's my tuppence-worth:
If you son doesn't want to go, he doesn't have to. Simples. But, I would make sure that he is making this decision from an informed position rather than one of ignorance. By that, I mean, that you should talk-up the positives of him going. You don't have to make the decision for a couple of months; it's not like it is urgent. Also, take this opportunity of the summer holidays to encourage him to go on sleepovers. I'm not surprised that he is daunted by going away from home for a week, if he doesn't have the confidence to stay with a friend. If he can't manage that yet, can you set up a tent in your back garden for him and a friend, so that he can experience literally not-sleeping under the same roof as you?
The talk about not being able to get there during the night, is a bit of a red-herring imo. That's just your anxieties playing up, and though you say you haven't discussed it with him, he will be picking up your anxiousness from your tells.
I can understand some of the anger from using the term 'child-led family' - and I say that as someone who would describe themselves as child-led. You can be child-led whilst encouraging new experiences and you can be child-led and say 'no' (it's more about the unnecessary automatic 'no' when there's no good reason). As I said at the start, if your son doesn't want to go, he doesn't have to. But ensure that he is making an informed choice.
As for 'home-educating for a week' I'm glad to see that you've stopped saying that, as it's a ridiculous phrase. We home educate. You would just be skiving or not going to school with the school's permission. To home ed, you would need to deregister, and then your son may not get a place at the same school the following week. Given's Jon Platt's recent court-case, they (LAs etc) are coming down hard on people who try to deregister to get out of paying a holiday fine.