What's making me scream today

This week has been a tough week not only for me but for some of my family members. My mother called me early on in the week to inform me that my sister has gone off the deep end. We have a family business and my sister has been running it. And basically she has ran it into the ground. I don't really want to get into details but she's really done a number on the business and the trust we have for her. There has been a feeling like things weren't right with her but nobody thought she could ruin the business over it. I don't know what exactly to say to my mother, she's very hurt and feels responsible because she'd didn't step in earlier. I just find myself very angry at how selfish my sister is. She's always been a self centered type person but I never knew she could be so outright mean with her selfishness. Especially to my mother they have always been close. So anyways this is going to be an ongoing situation. But today I want to scream out WHY ARE SUCH SELFISH BRAT???

Thank you for listening.....