How can I show my brother that forgiveness is a choice so we can forgive each other and move on?
If your brother is hesitant to forgive, as you say, it is his choice. In my experience, when people are hesitant to forgive, they often misunderstand what forgiveness actually is. A common error is this: The person thinks that in the forgiving, the injustice is wiped away to such an extent that it really was never an injustice in the first place. Yet, a true understanding of forgiveness is that what happened was wrong, is wrong, and always will be wrong. What changes when we forgive is our response to the person who acted unfairly. We begin to see and appreciate the inherent worth within that person. See if your brother might be more open to the idea of forgiving when you explain this to him. I wish you the best with this.