I'm going to refuse to lend to my brother
Why do you want to refuse to lend?
He didn't even tell me about why he needed the money. I hate him for that
I can understand you're want to know where your money's going. Maybe he's embarrassed? You should ask him.
I can't ask him. He deleted his Facebook and blocked my number so I can't talk to him.
That sounds very shady. You have a right to know what he wants money for. If he refuses to tell you, you don't have to lend him the money.