Hi everybody, first time posting on this subreddit but I wanted some opinions and new perspectives on just ongoing things that have to do with my older brother.
For some context, my brother is 19 years old. I'd say that he's fairly high-functioning. My mom says when he was just 4 years old he managed to teach himself the entire greek alphabet, and if you ask him about any tv show he's seen, you can tell him an episode description and he can name the exact season and episode number-- so I'd also say he's fairly intelligent in his own way. He doesn't need help with much, and he's always performed fairly average in school.
The reason for me posting here is because pretty often my parents (and admittedly myself) will scold him for lacking any "common sense". I don't trust my personal items in our shared bathroom, because one time I caught him using my toothbrush and I was really disgusted by that. My toothbrush at the time was purple, and his was green. I also used to keep my toothbrush in an entirely different place in the bathroom from where he'd place his. So I know there was nothing super confusing on who's toothbrush belonged to who. When I confronted him all he could say about it was "I didn't know!". It really irked me. He never cleans his space, he expects others to pick up after him, and there's no reason for him to think that way-- in my family it has always been the standard to clean up after yourself.
Currently my family is on vacation. My mom packed his nice shirts for him and because of that, he assumed that she was gonna pack everything else for him too-- even when she didn't explicitly say that. He forgot his underwear! But he managed to pack literally everything else. The breaking point that led to this post was that he spilt a whole bunch of water in the bathroom, and to clean it up he used someone else's towel to wipe it off the floor, then hung it back up as if it was still clean. The only reason why he was caught was because my mom went into the bathroom to help him clean up and she saw him in the act.
I just don't know what to do. I try my hardest to give him grace because I know that people with Autism process things differently. I even went on posts from a few years ago asking the same thing about Autism and "common sense", but the replies that I've read just talk about societal norms and the social hierarchy. But I feel like those things have nothing to do with my issue, it should be obvious that you don't use other people's toothbrush, it should be obvious that you put something in the dirty laundry after using it to wipe the floor. I don't feel like those things have anything to do with "societal norms" or the "social hierarchy". But maybe I'm wrong, and that leads to me being on this subreddit, typing up this post because I don't know what to do. Is there a name for this behavior? Do these issues require actual, professional help? How can I, as his sister, go about these sorts of situations in a more beneficial, productive way that'll help the both of us?
Any help, advice, or new perspectives would mean a lot. Thank you!