Well I am autistic and I can share with you a story that reminds me of your son and how others just don't get it.
My aunt was visiting from Texas for the first time in 12 years (I'd been there in that time, but anyway...) and my mother had this thing planned for her family and ours (my aunt, uncle, two cousins, my parents, my sister, me, hubby and our two kids) to go to dinner at a restaurant 45 minutes from where I live at 6:30PM. No problemo. Until she changed the location and the time at the last minute. I can't deal with that and so I ended up not being able to go and instead spent the rest of the evening at home in tears. I REALLY wanted to see my aunt, but I couldn't go. The restaurant she switched to was farther away, I didn't know exactly how to get there and there was no way I could have made it in time. They said it was fine if I was a little late, but none of this was in the original plan. It still haunts me, and this happened last year. I do not handle changes in plan or routine well without advance (read: at least 24 hours) warning. It's like it just ruins everything.
So your son's internal struggle is one I know well, poor little guy.
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Curiosity is not a mental illness.
Homeschooling Aspie mom of 2 kiddos on the Spectrum.