Is she handling him wrong?

My brother is 7 years old, turning 8 in 2 days. My mom is always telling him that’s he’s fat and he needs to stop eating so much because he’s going to die or have a hard time breathing. She doesn’t do it in a nice way either, she’ll literally shout at him that he’s fat. I understand that he’s not my child but can’t that lead him to an eating disorder if he continues growing in that kind of environment?