Sister needs to know her role in dealing with sibling’s weed use

I don’t want to drive him away or act like a third parent. My hope is that I can offer to be a listener instead of a messenger. How can I do this in a way that will communicate my love and concern, and help him share his feelings instead of shutting down? —

Your parents are asking you to cross a boundary.

Be a sister. That’s your prerogative, your job and your place. It can also involve all the listening and loving and even WTH-ing you feel moved to supply in the course of your normal relationship with Justin. But not as anyone’s agent.

The problems here predate the weed anyway, and are possibly the soil in which it grew. You say Justin shuts down for hard conversations. And your parents’ weed is bad/”religious and moral responsibility” code-orientation hints at an authoritarian parenting style. Authoritarian meaning a strict set of rules and expectations they’ll be followed, no discussion.

If true, that’s suggests that Justin has been trained either to live exactly as his parents expect or to make sure any deviations from their rules are on the sly and undiscussed.

Dialogue won’t spring from this dynamic naturally. Because what’s to discuss in “their moral code is that weed is bad”?

Tell your parents no, you won’t intervene.

In case they ask your advice: If they want Justin to talk, then they need to listen. If they want to do the talking, then they can expect deaf ears.

If they want a loophole, through you or otherwise, then they need to accept there isn’t one. If they just want a weed-free household, then they need to ask Justin to quit using or move out.