Thiele doesn’t just zoom out in space, he zooms out in time as well. The phrase “He grew up to be…” gives us this feeling of time passing, which again helps create this kind of epic, poetic, timeless feeling around Storm Boy.
In one of the examples below we simply say “Amelia was…” and in another we use the same “Xavier grew up to be…” phrase, so you can see the difference. If you want to get that timeless quality, try using “This character grew up to be…” or something similar.