What is the ruling on donating blood in infidel countries if it is most likely to be given to a non-believer, and does the ruling differ if the blood is to be given to non-believing children suffering from blood diseases and in urgent need of platelets, and is it true that blood donation is not obligatory?

It is permissible to donate blood to a non-combative disbeliever, based on the Almighty's saying: (Allah does not forbid you from those who do not fight you because of religion and do not expel you from your homes - from being righteous toward them and acting justly toward them), and based on the story of Umm Asma, whose mother was a disbeliever, and the Prophet commanded her to maintain ties with her. As for a combative disbeliever, it is not permissible to donate blood to him, because that would be aiding him against the Muslims.