Question

Let the night sky cover him as he dies.

Answer 1

Oh! Okay, now this makes sense. So from what I got from this, the weaver girl is taking a dead man to heaven. But the allusion of the girl helps develop a theme of some sort of ancient mythical tale in hopes of making it seem more real to the reader. It also helps develop the theme in a way of despair. Why despair? Well because a man is dead, most likely his own doing, because he can't be with the woman he loves. 

Answer 2

Here you go

The speaker offers a final wish for the dying man in the last stanza. He hopes that the man will meet the weaver girl in death and find comfort and acceptance. The allusion helps develop the theme that everyone deserves to feel accepted and loved.