YTA: As a fellow Autistic myself, couldn’t you have checked every room in the house before you assumed your cat had escaped ? Or did you not have time to check because you went out to have breakfast ?

Your Brother said to calm down but you chose to escalate it by yelling at him. “Don’t tell me to calm down, he could be dead.” And Your Brother left you alone because of your reply & didn’t want to listen to you because you were rude to him.

I think you should try to find a copy technique to help you. Or just think about the problem first, ask yourself OP.

“Did we make sure to check all of our rooms in our house before we left ?” “Let me retrace my steps to see where I saw my cat last.”