AITA for not taking care of my 10 year old neice during vacation when she threw up on herself instead of taking her to the hospital?

So my brother and his family were going on a 2 week vacation. His wife couldn't make it and it was last minute so my parents offered me to go with them because they had an extra ticket. They decided to go to Japan and I haven't been there in years so I thought why not. We stayed at a nice hotel and I had a good time there with my brother's 2 kids. There's a 14 year old boy and 10 year old girl and both are generally well behaved though I think the girl might have been spoiled a bit. My brother was clear with her that she had to behave and not make any demands.<br><br><br>I got food poisoning on the 9th day and had to stay in the hotel. My brother went on his own with his kids and when he came back said his daughter had thrown up on the train and he yelled at her because she was being stupid and said she had to go to the bathroom but she didn't go she just threw up on the train. I said she probably couldn't hold it but he said it doesn't matter she was sick to her stomach she should've gone to the hospital instead of throwing up on the train and gotten sick all over her clothes. I said maybe we should've cleaned her up but he said no she needs to learn to take care of herself and not be stupid. I just thought he was being too harsh on her but then again I was sick and staying in my room and had no idea how bad it really was. Did he overreact?