I'm glad we're on the same page.I wasn't saying his kid was an aw. Just saying some kids need to learn the consequences of actions.
Like mentioned, the kid is getting hurt, freaking out, passing out from not breathing and going limp. She will survive and eventually grow out of it after she is mature enough to realize there are better ways of dealing with "whatever issue" puts her in that state.
And NO, do not leave the kid unattended... nurture and love, not abandon.
As for disciplining children, my sil has a problem cold, but won't discipline. He gets around me or my wife (when his mom isn't around of course) and he knows we won't take his shit, so he's a good kid around us lol.