In Romeo and Juliet how does the Prologue of the play relate to Act 5 Scene 2?
Most of the prologue relates very well to Act V, scene iii, but I will help you stretch the truth to fit scene ii.
Scene ii is a scene between two friars. One is Friar Lawrence who hired Friar John to get a message to Romeo. Friar John uses the scene to confess to Lawrence that he could not get the message through to Romeo because of the Black Plague... or the Black Death.
This is ironic because the prologue refers to their "death-mark'd" love.
Another point of interest would be the "star-crossed lovers" because this would mean that the two of them are together quite unlucky. This message not getting to Romeo is the most crucial detail of the fifth act because this information would have saved two lives and they would have lived happily ever after. However, because it doesn't get to him, the prophetic prologue is fulfilled.