Final answer:
Mr. Perpich advises Brian to address his negative attitude as it is affecting other students.
Step-by-step explanation:
Based on the provided information, it appears that Mr. Perpich, Brian's teacher, has given him advice on his attitude.
Mr. Perpich tells Brian that his attitude has started affecting the other students and advises him to talk to someone if he doesn't want to be at school.
This suggests that Mr. Perpich wants Brian to address his negative attitude and find a way to improve it.