When he introduced himself, I asked our First Mate why he was going along with this. He said to consider him summoned for a task... I have no confirmation, of course, but it makes me wonder if he is like my daughter in that way.

That is, summoned to do a task for the chance of a reward. In her case, it was a wish but I can't say that Davy Jones is motivated in the same way.

[Hey she doesn't get it either.]