The 'children'?

It seemed very odd to me that Isak and his daughter-in-law viewed the 3 hitchhikers as "children". Like when they told the unpleasant bickering couple to leave because of the "children". And there were couple other places were they acted like these three were teenagers. But really, those three looked to be in their mid twenties or older. Is this a Swedish thing? Someone's a child till they hit 30 or so?