Mental illness as an autistic child.

I can say with certainty he doesn't care about how things work. It's more of a 'signs of damage' kind of thing. He likes seeing the aftermath of the destruction he caused. There are a lot of holes in my drywall from that. Also, he threw eggs at the neighbors houses (that was a fun time). Drops items off the deck to see how they break (including a dog once). I've tried redirecting him by putting together chunks of legos and letting him smash those. Sometimes that works. The least destructive redirection I've got is him simply pouring a cup of water from the deck to the patio. The splash of the water seems to calm him a bit. He has a major attraction to water.

I'm sorry, that's really hard. You're probably doing all the right things, it's just frustrating knowing that even doing all the right things does not lead to any answers.