The issue is not “what Paul said”, the issue is Paul’s sources. What are the sources of these claims? The sources are scriptures and revelation. Certainly being dead only happens to people that are alive, but there are literally thousands of stories from antiquity about people doing all kinds of things that only living people do, about fighting, dying, and dying and coming back to life, etc., and it is widely accepted today that the vast majority of those stories are about people who never existed.