parenting

how do i get my 22 year old sister to realize that yelling at her son or raising her voice at him for being a toddler will have a bad effect on him in the future?? she recently yelled at him for running around in their yard because she wanted to go to walmart, and i felt bad for the kid because number one, he clearly doesn't like his carseat, and number two, he was just being a toddler. i was(and still am) the kid who got yelled at for just being a kid and it forced me to grow up at a young age because i thought i wasn't allowed to act my age or else i would get judged. he's only two years old, and i can almost 100% guarantee that when he's old enough to realize he's getting yelled at and punished for acting his age, he's going to go down the path i did. i don't want my nephew to be traumatized for the rest of his fucking life. 

signing off, vinnie.