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 ask family to stop commenting on your weight, use this factual base: identify the visit, topic, money, photo, event, care task, or comment that needs a limit.
Offer a proportionate next step
Match the size of the request to the relationship and to what the recipient can reasonably decide now. State what is allowed, what is not, and how you will respond consistently. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Protect privacy on both sides
Do not threaten access to children or elders as punishment, and do not debate the entire family history. Use safeguarding, legal, domestic abuse, or emergency support where safety, custody, or coercive control is involved. Use the most private legitimate channel available and do not share the exchange to recruit support or pressure.