There is something we face in Western countries as you know, which is related to the doctor. Is it a condition that the doctor has to be a Muslim?

The doctor, who should decide break of fast because of sickness, has to be trustworthy and experienced. His being a Muslim is not a condition. Al-Harith ibn Kaladah was not a Muslim; nevertheless, the Prophet (peace and blessings be upon him) authorized him to give prescription. Truthfulness and experience are the basic requirements and being a Muslim is not a condition. This is what we should do in Western countries.