I’m so happy to see Hazel back. I honestly didn’t expect it, I was thinking about it but didn’t actually think they were going to bring him back, also he’s old! He got to live his life, that’s so cool! He’s honestly an amazing character and while I don’t think he’ll play a huge part in this season it’s still cool to see him.
Okay so, Hazel found out the world was going to end in 1963 as well, after living in the past and reaching the date (November something) so I’m guessing he and Agnes kept time travelling back so they would grow old and didn’t face the apocalypse again. Agnes was already old, she was 60 I think, and Hazel looks ancient now so I’m guessing she died of old age. Which… Really sucks, but we all go at some point.