Success in that Nathan enjoyed reading it at any rate.
I did up photos of everyone we have taking care of him and each person got their own two page spread. The first page was: "Can (name) take care of me?" with a picture underneath. When he flipped it up, there was a big YES! underneath.
The second page said when the person would take care of him (at Beavers, while Mommy is busy, etc.) and listed three fun things he did with that person: play games, make pancakes, play hide-and-seek.
I threw in two "no" examples: our two cats. Can Ceili take care of me? NO! Don't be silly, she's just a cat! But I can take care of her.
It worked like a charm. Nathan thought it was hilarious and asked to read the book again and again (thus winning half the social story battle).
We'll have to wait a bit to see if it helps to relieve his anxiety but hopefully the message will sink in and have a solid subliminal impact.
Nathan has been really bored with traditional social stories. Reading them was a chore he endured, which really doesn't help with getting the message across. I think the combination of humour and surprise will make a difference. He's already read it more voluntarily in one day than we usually manage in a week.
Bonus level: he noticed the empty pages left over in the photo album I used and asked if we could add more story to them. Seizing the opportunity, I asked him who else could take care of him and he started to brainstorm options with me. Only a few but it's a huge mental step that takes him away from believing I'm the only one who can take care of him.
School seems to be going better as they develop a more predictable routine and use the visual schedules effectively. Nathan even weathered a substitute teacher with minimal trouble. Hopefully we're turning a corner on this particular crisis.