1) Who is We?
Is it just the OP, i. e. the younger sibling, asking for a way to tell something to their brother, or does it include their parents also? If so, which one of the parents or both and do they want to tell them at the same time or one after another? Also, coming from their parents or their younger brother certainly makes a difference.
2. What about the situation?
The biggest problem with that is the basic attitude towards every problem: You are right and I have my peace.
Perhaps, that's indeed his attitude to every problem, although offering a solution to that would be beyond the scope of IPS.SE. Apart from that, we don't know much about those problems. We can't judge what's wrong about the brother's response in the second paragraph. The OP only shares more details in the third paragraph, but there the situation involves their parents - see (1). It's also not clear, if that's exactly the situation the OP wants to see solved, or an example to make clear, that their brother replies like that to their parents, too. So, is it relevant that the OP and their parents have to clean up the table themselves, for example?
3. What has been tried so far?
Tinkeringbell asked in a comment
Since you already seem to know what you want to say, have you actually tried saying exactly that? How did your brother react to that? Why not let your parents parent your brother?
yet didn't receive a reply. But it would be good to know, what approaches have been tried so far, for users to not repeat that in answers.
4. What's the goal?
How can we tell him how annoying he is in a simple way
Does the OP merely want to tell their brother, that he is annoying? And they hopes for answers consisting of sample phrases that may or may not work? And then we're back at (3): Did they already tell him that it's annoying?