Write from facts rather than momentum
Pause long enough to remove accusations, assumptions, and details that belong to someone else. For a message about how to support someone grieving their mother, use this factual base: use the person's name and relationship when known, and avoid details the family has not shared publicly.
Offer a proportionate next step
Match the size of the request to the relationship and to what the recipient can reasonably decide now. Offer one concrete form of help and remove any expectation of an immediate response. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Protect privacy on both sides
Do not say everything happens for a reason, demand strength, or center your own similar loss. For immediate risk, traumatic circumstances, or a person unable to stay safe, use local crisis or emergency support. Use the most private legitimate channel available and do not share the exchange to recruit support or pressure.