Me (thinking of a house boat as cosy if a little odd-shaped, just right): that's nice- and what sort of boat would you be?
Big Bro: I would be a rescue boat, and Little Bro would be a life boat. And Dada would be a sinking boat that we are coming to save!
How's that for family dynamics?
Postscript, a few hours later: I should add that Dada is not the personification of a sinking boat!! I just thought it was cute that Big Bro wanted to help him.