Your Protestant friend is probably working on the presumption of sola scriptura: Unless he can find record of a near-death experience on the plain face of Scripture, he believes it unbiblical. Rather than argue with him over near-death experiences – on which the Catholic Church has given no opinion, so one is free to think that they are possible – you might ask him to attempt to prove that a Christian must find all that he is allowed to believe within the plain meaning of the Bible alone.
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