bathtub scene

How very odd that mum walks in and even flicks water at the son as he's sitting in the bathtub. I mean, he looks 15 or 16! He didn't protest. I would love to know how other people experienced this scene. It creeped me out. I thought wtf is wrong with this woman? Is it just bad writing? Are Australians just a wee bit different about such things? I have no idea.