<human>: Can you provide a brief overview of the text?

Today at the mall, my two 1/2 year old sister wanted to go play in the children's play area for a bit. She climbed into one of these makeshift cars and these two boys (brothers, I'm pretty sure) joined after a few minutes. As she was laughing and having a good time, one of them shouted at her, "GO AWAY!", and tried pushing her out of the car. My sister shrugged and left. THIS broke my heart, just thinking about my little sister ever getting bullied in the future and how kids can just be awful sometimes.

A few minutes later, my sister went off to play on the slide. These two brothers were still in the car when this little boy came along (probably around my sister's age) wanting to play with the car as well. So, he climbed in. Suddenly, I see the brothers punching the little boy in the face repeatedly telling him to get out. He's bawling his eyes out as his mom runs and picks him up, scurrying away.

The kicker? The brothers' father was sitting RIGHT there, maybe a couple meters away, unmoved by all that happened. All he did was stare at them without a care in the world. THIS made me "WTF!" really hard.
<bot>: little sister gets bullied by two brothers, same brothers punch other little boy in the face, brothers' father does/says nothing.