Is it permissible to persuade an atheist to Christianity, given that the People of the Book are closer to Islam, in order to avert his danger from society, and then attempt to persuade him to Islam later?

The People of the Book are closer to the truth than atheists. However, this does not justify inviting an atheist to Christianity or Judaism. Rather, the duty is to invite them to Islam, explain its true nature, and remove any doubts they may have. Guidance is solely in the hands of Allah, as He Almighty said: ﴿Say, "O mankind, the truth has come to you from your Lord. So whoever is guided is only guided for [the benefit of] his soul, and whoever errs only errs against it. And I am not over you a manager."﴾ and ﴿And say, "The truth is from your Lord, so whoever wills - let him believe; and whoever wills - let him disbelieve."﴾ This verse is not a permission for both options but a warning to whoever chooses disbelief after the clear exposition. Specialists have answered the doubts of atheists concerning Islam, whereas corrupted Christianity does not provide convincing answers to some of the atheists' doubts related to matters of faith and monotheism within it.