Search came up with nothing so I'm gonna ask; before I unpause my game, what happens to the house and game if you don't have kids? who gets the house after the no-kids-parents die? the sister/brother?

You have a game over situation.

You can only continue if you have children.

It should also be mentioned that each generation must have at least one child by birth or adoption, and that child must be living in the house or have gone off to college, in order to avoid the 'game over situation' that Moonlyght referred to. Children produced in previous generations cannot inherit the house.