That would depend on which part of the situation he's asking about! The Roaka can explain the eruptions, the apparent explosion-and-rebirth of their elderly-turned-young, and the properties of the Youngdrink, as well as the rationale for its use. If pressed, the Roaka's answers will make it clear that they don't really regard their visitors as so different a species that this might be alarming or unnecessary. This is completely acceptable to them - why are you so confused?

They cannot, however, explain the aging characters may undergo. That is completely new to them.