Does God forgive Christians after millions of years, or is it unto eternity? What is the way to escape the tribulation of religion at the time of death? And does God answer all prayers?

He who dies as a Christian, Allah will never forgive him, due to the generality of His (the Almighty's) saying: "Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills," and His (the Almighty's) saying: "Indeed, those who disbelieved and committed wrong - never will Allah forgive them, nor will He guide them to a path Except the path of Hell, wherein they will abide forever." However, if the Christian embraces Islam before death, Allah will forgive him all that has passed, due to His (the Almighty's) saying: "Say to those who have disbelieved [that] if they cease, what has previously occurred will be forgiven for them." It is incumbent upon the Muslim to strive for the guidance of his Christian sister, and to be saved from tribulation at the time of death, one must constantly remember Allah, avoid attachment to other than Allah, and dedicate time to acts of obedience.