Billy Dunne has no communication skills
What Rod meant: Try talking with Daisy's husband, explain your concerns regarding his wife's drug use, then he might be able to get through to her and help.
What Billy heard: Approach the guy accusingly, say every sentence in a passive-aggressive way, if he's not having it (since you and his wife were/are in love and now are singing into each other's mics every night) start insulting him and then wrap it up by throwing both of you onto the table/floor and punching the shit out of him (in front of everyone).
