The notebook was sent to the Professor with more than enough time for there to be repercussions.
More than enough time to shut him down.
So the question is why did he send it so far in advance.
I don’t know to tell you the truth. The guy was/is a nutball supreme evidenced by his actions. My guess is that his orals didn’t go well at the end of the year critique of his graduate work. I don’t know what kind of drugs/pills he may have been taking, nor do I know whether or not he is just crazy crazy or driven that way because of stress, uncertainty, etc..
One thing sticks in my mind - his mother when called telling whoever was on the line “you have the right person.” (or words to that effect). This tells me the parents were aware of what a nutcase this son might be.