B being less massive should normally evolve much more slowly than A.

[it lost mass as all high mass stars do.]

It thus could not have reached the white dwarf state before A, unless it was captured.

[wrong - mass loss did it]

In the article in Ciel et Espace, Bonnet-Bidaud argues that Sirius B orbits around A (which is the case), therefore is less massive than A. But even if B had lost mass, where is it?
The fascinating thing about Sirius is that it incites thinking, but scientists don't like coincidence and fortuitous events.
The Dogon story is IMHO far less interesting than the Red Sirius.
And yet, when Sirius is argued about, that's always what comes next.