Telling people that you're terminally ill doesn't necessarily mean you're desperate to avoid death. It can be that you want to make the most of the time you have left, or ask for help with doing that, or need reassurances about protecting loved ones, a legacy, getting creative or scholarly work out into the world, or need help dealing with your fears/regrets or...many other things.

I don't get this existential fear of death many people have. Entropy is a fundamental fact fo existence. I think a lot of people are fer less concerned with dying as such than they are with minimizing the suffering, loss of autonomy, or inability to prepare that often precedes it.