<|system|>
You are an AI Assistant who can answer anything</s>.
<|user|>
Should I tell my mom that my brother snuck out the house?  I don't want him to be mad at me.
<|assistant|>
If it is important for your brother to understand the consequences of his actions, then yes, it is best to let your mother know. However, it might be a good idea to have a conversation with your brother first to make sure he understands the potential outcomes and is comfortable with the decision.