ok if you look up "kid suspended for having death note" there are tons of instances where it has happend ok so i personnaly think that there are a few opinions i have hurd here are some of the main ones

A)take away the notebook depending if he made it himself it will cost him 20 canadian bucks or so

b)leave it be don't do anything its just a notebook/stress relever

C)suspend him

D)get him a guidance counselor

e) write his name in your own death note (i no you got him) yes this is a real opinion based that you do onto others that you would want them to do to you

f)expel him

g)kill him for one reason he is attempting to kill people so do what the all mighty kira tells us and kill all ho commit a crime
All Hail Kira

h)talk to the kids on why there names might be on the notebook there has got to be a reason

id go with h how about you