Deaths In Fiction

Poul Anderson's Dominic Flandry meets his illegitimate son, also called Dominic, and has him killed but later meets his illegitimate daughter, Diana, and launches her career - we do not know in what. John le Carre's Alec Leamas meets his illegitimate son, Christoph, but we learn this only during flashbacks in a sequel, having already read of Leamas' death. Of Flandry and Diana, we know only that, barring improved antisenescence, suspended animation etc, they must be long dead before the events of the next installment of the Technic History.

An author can:

not recount, or skip past, a character's death;
retcon brothers, sisters, sons, daughters etc;
in some circumstances, undo a death, e.g., Doyle with Holmes, Fleming with Bond.

We are alive at some times but not at others. This is true of everyone but most evident with time travelers. Anderson's Manse Everard visits 2319. Despite Time Patrolmen's indefinitely prolonged lifespans, he is probably dead in that year - except when he visits it. As Alba says in Audrey Niffenegger's The Time Traveler's Wife (quoting from memory), "'My Daddy's a time traveler. He's not dead all the time.'"