In order for this to make any sense, you have to taboo some words and expand out the metaphysics, and in particular what’s meant by the word “death”. The scenario you’ve described sounds more like “teleported into an alternate universe” (or copied into the new universe after being destroyed in the old one), with the destination universe being an afterlife. The scenario says that you’re having a conversation, and you can’t do that without a working brain, which is my definition of being alive. But the “teleported into an alternate universe” hypothesis isn’t very hard to test; you could look for differences in the laws of physics, or look through a portal into the original universe, for example.
In order for this to make any sense, you have to taboo some words and expand out the metaphysics, and in particular what’s meant by the word “death”. The scenario you’ve described sounds more like “teleported into an alternate universe” (or copied into the new universe after being destroyed in the old one), with the destination universe being an afterlife. The scenario says that you’re having a conversation, and you can’t do that without a working brain, which is my definition of being alive. But the “teleported into an alternate universe” hypothesis isn’t very hard to test; you could look for differences in the laws of physics, or look through a portal into the original universe, for example.