how does dr. sadao's humanity get victory over all other factors?

Dr sadao like the evening fog that had arrived with a certain sense of vagueness and unsurity , which represents the mindset in sadao and his wife and their dilema of what should they do with the american prisoner of war,. But human values take precedence over narrow sectorial considerances and  the bond uniting all the humans narrows the differences that exist within them.He was oblidged to help the refugee as he was in a pathetic condition and much needed medical aid.
But Sadao being a kind hearted generous and practical person resolved to help the poor human evenn if he was his enemy!