The best way to get back at someone is to have a great life. Ignore him and block him, and carry on with your great life.
He’s obviously insecure, fragile, and arrogant. Move on - you’ll never win anything by stopping to his level, and you’ll never convince him to change his ways by putting him in his place. The older you get, the more you realize quickly people just aren’t worth your time.
When you see him next, just ignore him. When he gossips about you to his brother or your friends in an attempt to get a rise out of you, laugh and ignore him.