Naturally, the pain of others is something you shouldn't brush aside, especially if they are close to you. [and he's taking a complete shot in the dark here, but indeed, he thinks the man is crying for his loved ones. it's the only thing that makes some sort of sense.]

After all, if someone hurt my son, I may have to do something drastic, moreso now that I know how much of a failure of a parent I am.

[perhaps that is not something to say to a stranger.]