Make the first sentence usable
Lead with the reason for writing so the recipient does not have to decode a long emotional introduction. For a message about how to invite estranged family to a graduation party, use this factual base: give the event, date, location, relevant history, and what kind of contact the invitation involves.
Reduce the work of responding
Offer simple options, a narrow question, or a clear update that can be understood without another conversation. Offer a simple way to accept, decline, ask a practical question, or choose a lower-contact option. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Respect the boundary already visible
Do not announce their attendance, use relatives to persuade them, or make a public gesture before they agree. Respect no-contact, venue safety, custody, and legal restrictions even when the event feels important. A block, explicit refusal, legal restriction, or safety plan takes priority over the desire to explain more.