Absalom never spoke to Amnon about this - 2 Samuel 13:22
Absalom showed what happens when the lines of communication between two people break down
He had every right to feel angry about Amnon rapping his sister
What went wrong is his refusing to talk about it and making no effort to try to resolve the situation - Amnon felt sorry for what he had done
Absalom's anger grew deep inside until it became implacable hatred
He waited for the right opportunity to order his servants to kill Amnon - 2 Samuel 13:28
Absalom paid a heavy price for his failure to resolve his conflict openly and peacefully