So Sarah and Kyle managed to save the world from judgement day in Terminator Genisys. They destroyed Genisys/Skynet.
I just remembered that John mentions to Kate and Terminator (Arnold) in Terminator: Rise of Machines while in the graveyard, that his mother died of Leukemia.
After Genisys, Sarah now lives a normal life but does that change the way she dies?
Or was John trying to hide the real reason for his mother's death by making up a story of cancer?