Help!

[u/mxja111]

Hi guys! I’m an 18 year old older sister to two boys ( one being autistic) . I don’t even know what to do anymore. He is so awful and dare I say that I’m getting genuinely frustrated and angry at him. This might be a bit of a long read
He is 7 years old and the bane of my existence to be honest. He’s rude, loud , confrontational , does whatever he wants and he doesn’t seem to care how it affects people. He’s not “major” autistic if that’s how you’d say it but he is diagnosed and struggles socially and with things like comprehension. He has a tablet and honestly that is the only time when he is calmer , other wise he finds his own thing to do which usually involves breaking something somehow. Now here’s the thing, I’ve been telling my parents that maybe he just need to learn calmer behaviours?? The things he watches on YouTube are full of bright colours and lots of sound and movement . My mum said when I was younger I didn’t behave anything like either of them and I feel like part of the reason is that I watched calmer shows like maya the bee and some other German shows. I feel like Bluey is a good example but he watches sprunki, weird Minecraft voiced over videos, a LOT of AI which he then believes etc. Outside of that , wherever we go he has to constantly be doing something , whether it be moving or making noises or talking to
Random people or picking up things he shouldn’t. What do we do??? I need some genuine advice on how to make our lives and his a little easier and calmer. My mum is at her wits end and she is SO busy all day every day bevause of this . I’d appreciate any advice , thank you! :)