In Sanctuary, Helen Magnus appears to have stopped aging, even in the first few years of the series (to say nothing of what happened in Season 4). But then her Father shows up and is in several episodes. Yet there's no reference to him having had any connection with the Source Blood.
Why didn't he die at a "normal" age? Will he not age, or is he aging extremely slowly?
In season 1, episode 10 Warriors, he's revived because the Cabal is interested in what he knows. It is not explained exactly how, but according to Wikipedia, citing the audio commentary for the episode on the DVD:
In writing "Warriors", Egan wanted to reintroduce Magnus' father Gregory Magnus from the webisodes; there were plans to introduce him in "Fata Morgana", but the idea did not make it to the final episode. Gregory was written not to have the longevity of his daughter. Egan decided not to include a full explanation of how he survived a hundred years without aging, but wanted to hint to the audience that he was in fact cryogenically frozen by the Cabal.
Presumably, then, he is aging at a normal rate and will die within a few decades.
Later on in the series, there are a few more clues that pop up about Gregory Magnus's life.
Gregory Magnus's long life is, like Adam Worth, due to having lived in Praxis for so long. However, because this is a retcon of the originally implied cryo-freezing by the Cabal, it leaves a gap as to why he left Praxis in the first place. The Sanctuary wikia page on him does say he left so he could make contact with Helen, when he was captured by the Cabal. However, I don't recall that being in an episode myself.
Oh. Okay then. Sorry didn't get that. Actually there is one possibility. Gregory could have taken some of the technology from praxis before It was destroyed and went into hiding and used it to help maintain his health.
