I thought i was the only one who thought this, but i also get the vibes too
Matthew has a ton of trauma. Which is why I think its better to stay away from the autism angle. Matthew obviously had his personality and development stifled by what happened but autism is something you're born with.
There is no indication he had behavioural problems before the accident (and evidently had no issues learning etiquette and such while living with his parents).
I’ve gotten further in the story and saw that.
I’m only on chapter 17 and I have to ask, does anyone else get autism vibes from Matthew? Normally I dislike reading disorders or conditions into characters but he literally has a chart for expressions, childhood delayed speech and seems to take things literally. I’m not counting hyperfixation because that just standard BL nonsense