Name the impact without exaggerating it
Describe who had to wait, worry, redo work, spend money, or make a choice with incomplete information. For a message about how to respond when you are worried about self harm, use this factual base: reflect what the person has told you, any immediate concern, and the practical context without diagnosing them.
Make repair practical
Offer the repair you can actually complete, with ownership, timing, and any limit stated honestly. Offer one manageable form of support and ask directly about safety when you have a serious reason to worry. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Let future behavior carry the proof
Do not shame, threaten, promise secrecy about imminent danger, or make yourself the only source of help. If someone may harm themselves or another person, contact local emergency or crisis services and a trusted nearby person now. A promise inside a message is weaker than a visible change in what you do after it.