Guess the mom's ability to see the truth is just there for decoration now huh

It’s kinda iffy on how it works cause it only works when someone tells a lie while consciously being aware of it. Vincent lied to her in the beginning by just phrasing it in a way that wasn’t a lie but wasn’t at all the full truth. The first son probably made a deal with the pirate queen to swear loyalty, and since it isn’t a lie that she’s actively doing it, the moms ability won’t activate.