Bruh..right before his illness means Whitebeard was already old.. Primebeard wasn't sick.. It was until Whitebeard became old that he only became sick. So if we take that Vivre Card at face value, Weevil = Oldbeard not Primebeard
But Vivre Card ain't a reliable source. Manga tells Weevil = Youngbeard not Oldbeard before his illness