Why use the word "blame?"  Why do you need to find someone to blame?  Have you ever tried to get help for someone?  It is very difficult.  If they are not openly threatening themselves or some else, there is nothing you can do.  The help could have been offered, (Professor said he was referred to Counseling) but he had the legal right to refuse (he was 23 years old). 

At this point, the focus needs to be on the community (students, parents, administrators).  They need  prayers and support.  The "blame game" is not helpful.