Annoying my bro is

I went to the mall with my mother and brother to buy some stuff because there was a sale. We aren't really planning to include my bro to the trip but apparently, he saw us and rode the CRV right away. At first, he was silent. I thought he would behave this time. Little did I know, he was just waiting for the right moment. When he saw what he wants, he took it. If we disagree with him, he would scream and everyone will look at us. It's embarrassing. Every now and then he would scream. Well, he is still my brother so I have to put up with it.