If someone close to you was getting so obsessed with longevity that it was negatively affecting the other aspects of their life, then it might be reasonable to talk them about getting professional help. It could be a difficult discussion, but it might be the right thing to do.

But c’mon, suggesting the same to someone on the internet who hasn’t displayed any of those issues is ridiculous.

You don’t actually stand by that do you? Everyone who thinks longevity is a realistic possibility has some deep-seated issue about death?