It wasn't just their yacht he was after. Before he killed them, he had them sign powers of attorney giving him access to all their money, and they even had to put their thumbprints on some document. And yes, the wife was in it just as deeply as Skylar. I just finished reading Vanished At Sea about this case and I couldn't put it down. Unfortunately for Skylar and his wife, they weren't very smart about anything they did. They're never gonna breathe free air again, though, so at least they're where they belong. Nah, come to think of it, they belong at the bottom of the ocean.
Just drink lots of Kool-Aid, and take one of these blue pills three times a day.