Violet just watched her grandfather deteriorate, including suddenly losing his balance and becoming unresponsive. I can picture a drunk Finn stumbling around or slurring his words and Violet suddenly thinking her dad is sick like her grandpa was. Violet is perceptive and that kid does not need that kind of trauma added to her grief and confusion.
Minimizing her exposure to Finn's choice to drink is the top priority. Then Liz should call Chase and Tracy to let them know Finn is in trouble.
Protecting Violet is also protecting Finn because he is going to HATE himself if the drinking hurts/scares his daughter, regardless if it's physical or mental.
And I like Liz being a bitch in this moment. She is shocked, probably scared, and jumped straight into Mama Bear mode...