Lead with the fact instead of burying it.

A softened opening does not reduce the blow, it only delays and distorts it.

The instinct when delivering unwelcome news is to build a runway: three paragraphs of context, a reference to how well things have gone in other areas, and only then the difficult sentence. The intention is compassion. The effect is that the reader spends those paragraphs sensing that something is coming, reads them with rising anxiety, and then encounters the fact in a state considerably worse than if you had simply said it. Suspense is not kindness.

There is a further problem. A buried fact can be missed entirely, or misread as smaller than it is, because it arrived hedged and surrounded by cushioning. Then the family finds out properly later, and the reasonable conclusion they draw is that you were not straight with them the first time. The trust cost of that is far higher than the discomfort you avoided.

Say the thing early, in ordinary words, without euphemism. Then explain: what led here, what it means concretely, what has already been tried. The explanation is where care belongs, and it will be read attentively because the reader is no longer waiting for the other shoe. Plain language matters especially here, because vague professional phrasing invites the reader to imagine something either much worse or much less serious than the truth, and both errors cost you a difficult follow up conversation.