Indeed, I hold that most Christians of the present time, whether Europeans (Al-Rum) or Central Asians (Al-Turk), are included in the divine mercy, Allah Most High willing, meaning those in the far lands of Europe and Asia who have not been reached by the prophetic message. For they fall into three categories:
1) One group who have never even heard the name of Muhammad ﷺ to begin with, so are excused
2) A second group who have heard of his name, his character, and the inimitable miraculous signs of truth (mu’jizat) that appeared at his hands; namely, those peoples adjoining the domains of Islam, and who mix with them, these being the unbelievers who deny the revelation.
3) And a third group between the two others, who have heard of the name of Muhammad ﷺ, but not of his character and attributes. Rather, since childhood they have heard that “a lying imposter named Muhammad claimed to be a prophet” – just as our children have heard that a liar called al-Muqaffa’ was raised up by Allah as a pretender to prophethood. Such people in my view fall into the same category as the first group above in respect to knowing the true attributed of the prophet ﷺ, for even though they have heard his name, they have not heard of how he really was, so how should the respond?
[Imam Ghazali – Faysal Al-Tafriqa (32), 3.96 – taken from: ‘Sea without Shore’ by Sheikh Nuh Keller]