If you claim that the latest bitcoins you bought are the ones you sold (and either claim a loss or a small profit).... How do you plan to declare the previously bought bitcoins if you ever need to sell them for banking fiat in the future?
I mean, if you do that you are basically claiming the latest bitcoins you bought are the first/only ones you got. You could have a hard time later proving you had some more when you yourself declared you don't.
Or maybe canadian law is different in this specifics.
Uh.... he's got lots of paper wallets. Pick the oldest one, then sweep some or all of it to a new paper wallet 1 to 2 weeks before you actually need to exchange it. When you finally exchange it, it's only 1 week old, declare capital gains or losses as appropriate.
A good idea in this scenario is to constantly move your paper wallets to new paper wallets every month.