I feel like the story is trying to say something more than just commenting on the transience of life, but I'm not too certain what exactly.
It could be a comment on enjoying the moment we're in, and the journey rather than the destination, but our disabled protags seemed to be having a mostly miserable time.
It could be a story on not giving up (The human doesn't give up on his journey, and the Elf doesn't give up on forming friendships with humans), but neither seem to really push the point hard enough.
So overall, quite enjoyable, but the muddled message (if there even is one) is a bit distracting.
Actually, as I was about to hit 'post reply', I had a thought; is it about letting go?
The disabled elf threw away her necklace from her past that was making her question whether to continue the journey, she had also let go of her hair which holds great significance in order to save their lives, the disabled human had let go of the idea of reaching an 'end' (setting the village as their end instead), and had also let go of his family so that he could continue the journey and start truly accepting the elf girl (and start calling her by name), and finally the elf with the book let go of the trauma of passing friends and went on to make another.
I think this idea is further back up with the page about the trade-offs, you have to 'let go' of something to receive something - you have to accept death to get close to the humans; as well as the the motif of elves cutting their hair during major life events - they're 'letting go' (or trading their hair for relief) of the past by doing so.
.... I'll continue mulling this over, haha.