in this scenario, in the world that they are in, I'd argue that it is- it would be mercy killing than prolong their suffering, while also allowing the distribution of resources to people who can better benefit from it in the long run. There's no assurance that the kid will get better, but a healthy adult (or kid) going weak because the resources lacked due to the sickly kid being prioritized MIGHT destablize the community
This is definitely understandable especially when you’re in war, apocalypse…etc (anything that’s making you lack resources)
If you know that the person regardless kid, teen or adult is going to die soon it’s best to not waste those resources and keep them for those who’ll both be able or recover from em and are helpful to do this and that

Wait guys remind me if Guwon is a child murderer or not so I know whether to feel bad or laugh