Just tell him you were wrong. Tell him you're sorry. Tell him you regret what you did every day. Tell him that if you could go back and change what you did, you would.

[ He sighs, patting the man's shoulder. ]

You owe him that, if nothing else. He should at least hear that from you. Whether or not he decides to forgive you is up to him. But I think it's hard for anyone to hold onto anger, when met with a sincere apology. Especially if their affection for the person was once genuine.