Anonymous wrote:Wait, who WOULDN'T say something to a little kid banging on a glass window? EVERYONE in my extended family on both sides would.
"Oh, that can break, don't bang on that. Here, do you want to play drums with this? Let's make some music."
+1
Also, little kids are notorious about telling other kids to follow the rules (whether or not they follow them themselves). That's really common behavior.
If you don't like spending time at your BIL's house, you stay at a hotel. Or you stay at his house and you do your damndest to follow his rules--you straighten things up, you redirect your kid whenever necessary--and you just let any critical comments roll off your back. It might not be tons of fun, but it's not going to hurt anyone.