The author of the post invented a character born today and who will live for 1010 years. The author’s character was described as “he”. You seem to think that this is wrong despite it not being your character.
Potentially more than zero, certainly fewer than the (large) number of births
today, and the argument is that one pronoun is (in)accurate for an individual...what we need here is “they” because there will as likely be a group of “them” as one alone.
