If a Christian converts to Islam, will that benefit him?

Islam is the final religion and the only one acceptable to Allah. Whoever dies upon a religion other than Islam is a disbeliever, eternally in Hellfire, as stated in the verses: "Indeed, the religion in the sight of Allah is Islam," and "And whoever seeks a religion other than Islam, it will never be accepted from him." Despite this, Allah accepts repentance and forgives whoever embraces Islam, for Islam nullifies the sins that preceded it, and one who repents from disbelief is like one who has no sin, in affirmation of Allah Almighty's saying: "Say to those who have disbelieved [that] if they cease, what has already passed will be forgiven for them," and the Prophet's (peace be upon him) saying: "Do you not know that Islam nullifies what preceded it?" And Allah extends His hand to accept the repentance of His servants at all times.