First-Aid to a Non-Muslim

Question :

When a Muslim applies first aid to a non-Muslim, does that make him his brother?

Answer:

If a Muslim applies first aid to a non-Muslim, or a disbeliever who is not at war with the Muslims, then that does not make him his brother. This is not unlawful for him, even if he is treating a woman. But he will be rewarded for the good he did, even if he was helping a disbeliever; Allah Almighty said:
"And do good. Truly, Allah loves the good-doers."

He also said:
"Allah does not forbid you to deal justly and kindly with those who fought not against you on account of religion and did not drive you out of your homes. Verily, Allah loves those who deal with equity."

The Prophet ﷺ said:
"Allâh continues to help His servant as long as that servant is helping his brother."

He ﷺ also said:
"Whoever is there when his brother needs him, Allah will do the same when he is in need."

Both of these Hadiths are in regard to the Muslim.

During a period of truce between the Prophet and the people of Makkah, the former gave permission to Asma' bint Abu Bakr to keep relations with her disbelieving mother. But if there is no truce between the Muslims and disbelievers, and if they are at war, then it is not permissible to help them in any way; in fact, doing so is one of the nullifiers of Islam. Allah Almighty says:
"And if any among you takes them as Awliya' (friends, protectors, helpers, etc.), then surely he is one of them."