Because they feel like life doesn't matter anymore. maybe they have been through a lot amd can't deal with it anymore and they are to afraid to ask for help. a lot of people who get bullied feel as though they should give up.
They could try feeding Nathan or changing his diaper. They should also check his temperature to see if he has a fever or something to that affect.
I hope this helped! :-)
This is rlly nice thanks hope you are also doing well :)