Then OP has to die in international waters. And I think ships usually count as part of the country they are registered in. So if you die on a cruise ship it still counts like dieing in that ships owner country. And its not trivial to move a corpse out of a country, there are laws about that. So the country they plan to die in very mutch matters.
I assumed international waters. I don’t think the home jurisdiction matters
Then OP has to die in international waters. And I think ships usually count as part of the country they are registered in. So if you die on a cruise ship it still counts like dieing in that ships owner country. And its not trivial to move a corpse out of a country, there are laws about that. So the country they plan to die in very mutch matters.