Ah, that's interesting. In my fanfiction, I had him rescued from his homeworld  Earth 964, which had been destroyed by a nuclear holocaust in 1964 which obliterated all human life (it was the world of Nevil Shute's On The Beach (1959), but  with Silver Age DC superheroes) while he was away, with him as the only survivor, and Willie Fawcett went to live on Earth-500 (my rebooted Earth-D in the Greater Multiverse), where he was eventually adopted by Kalel and Kara, the married Superman and Supergirl on that world, and Captain Thunder serves in the Justice Alliance there. So, will Captain Thunder end up in the JSA as a result?  And did he have a Thunder Family equivalent to Mary and Captain Marvel Jr on his home Earth?