DC1’s best friend (8) is here. Despite all my gentle chats, best friend is still really unpleasant, disdainful and snappy to DC2 (4). DC2 was making some silly noise earlier - because she’s 4, and y’know, it’s her house. Play date friend has been really shouting at DC2 to be quiet etc. Similar things have happened before and I’ve spoken to them all about being kind and playing nicely etc. Obviously I am trying to keep DC2 away from the bigger kids as much as possible but they are playing in the communal spaces of the house. Are my expectations unreasonable? Is this normal for younger siblings on a play date?