Answer: Cassie’s father wants Cassie to think carefully before taking a stand about Lillian Jean
Step-by-step explanation:
Cassie’s father had a serious talk with Cassie as he wants her to think carefully before taking a stand about Lillian Jean.
This can be deduced from the excerpt when he told her not to get mad but that she should clear her head and think sensibly so as to know whether Lillian Jean is worth taking a stand about or not.