[He simply nods at the first question, feeling no need to expand on it. After all he already said it, so it's probably just a confirmation.]

If it's a joke then it's only funny to them. If I were to choose I would say there are more chances of it actually being just a game someone has set up.

[He nods again as she accepts to stay for the meantime.]

I hope you don't mind parties, some of the people here are fond of them and will start one without notice if they feel like it.

[From his tone it's clear that he isn't one of those, he turns to return to his work but it doesn't take him far so he's still pretty much hanging around the deck with her.]