pba and csar- sometimes its not so simple to just “not go” to some places…especially when its a close relative like your brother. And if your not in MS_DC’s situation you cant judge him like that.
That being said, she must have not known better or she wouldnt have eaten the hamburger. I wouldnt beat myself up if it was my kid. However next time the situation arises, be ultra careful and help your daughter understand why its important that she eats different food then her cousins.