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 congratulate a friend on a sobriety milestone, use this factual base: name the milestone and, when you know it, the effort or meaning behind it.
Offer a proportionate next step
Match the size of the request to the relationship and to what the recipient can reasonably decide now. Offer warm recognition and let the recipient decide whether they want a call, visit, gift, or quiet celebration. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Protect privacy on both sides
Do not make assumptions about pregnancy, money, relationships, health, or what the achievement should mean next. Follow the person's lead on privacy before sharing their news or photos with anyone else. Use the most private legitimate channel available and do not share the exchange to recruit support or pressure.