Say the boundary in operational terms
Name the contact, behavior, topic, access, or commitment you will and will not participate in. For a message about how to support someone after an overdose death, use this factual base: acknowledge the death and the relationship while repeating only facts the bereaved person has chosen to share.
Define any necessary exception
If an exception is necessary, give it one purpose, one channel, and a clear limit. Offer specific practical presence, remember important dates, and let the person set the pace. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Respond to escalation safely
Do not ask how it happened, assign blame, use stigmatizing language, or turn the death into a lesson. Use trauma-informed crisis, bereavement, emergency, or professional support when someone may be in immediate danger. You do not need the other person to agree with a boundary for you to follow it consistently.