In this example they are talking about the virtue, or goodness of this man. That he may not have enough kindness left, therefore he is like something bad or evil that cannot die.
Anonymoustherefore he is like something bad or evil that cannot die.
So if we want eternal life, we should be evil? I don't know the story. Perhaps you do. I took the quote as a sarcasm, similar to "Tarnation! He's too mean to die!"