[Hm, potential for a brush with clairvoyance...]
Savannah rolled her eyes good-naturedly, more amused by her brother's comments than threatened or embarrassed by them. After all, it was Bast being Bast -- and, even though she had seen a variety of emotions from him, she always imagined this side of him to be like an angry kitten protecting its ball of yarn.
Letting the question of his purpose being there go for the time being, she said instead, as seriously as she could muster, "Now, Bast, you're old enough to make mature choices regarding alcohol. But if you need a ride home, I want you to know you can always call me."