Voluma:
Yes, that's very sensible indeed. But personally I'm a storyteller so I've half-deduced, half-invented. I tried to stick to what we already know (actually very little) but I needed a good reason to set the Captain off drinking so here are the results
...that's not to say I don't enjoy reading other peoples attempts of course, heh heh... ;-.
A little worrying about the Captain terrifying his niece with his drunken moods, but I like the rest!
Voluma:
Shortly after leaving university he was imprisoned for refusing to work on nuclear weapons
This wouldn't quite fit with the timeframe of when Calculus first appeared in
Red Rackham, which is the early 1940s. One would think that Calculus was quite a bit older than university leaving age when nuclear weapons were first being developed (although, it's impossible to tell), so I would have thought he might have been imprisoned for refusing to work on developing submarines, or something similar, during the first world war...?
One bit of back story that might be interesting to develop is how the Haddock family came to lose possession of Marlinspike. Of course, Calculus is the one who discovers that Marlinspike is actually the Haddock ancestral home and even buys it back for the Captain. There must have been some fairly reckless Haddocks in between Sir Francis and Archibald who went and lost everything!
Edit: Incidentally, my idea of a back story to Haddock's family was simply a musing and in no way am I encouraging anybody to go and write a fan fiction, or do something else illegal! Something to bear in mind here is that we shouldn't get
too carried away with inventing stories involving Tintin for the ol' copyright reason. Musings, contemplation and ruminations are just fine though :-)