Is there any book anywhere that couldn't be in need of a trigger warning? Think about Twilight or Lord of the Rings or The Great Gatsby. What would be helpful is for professors to do what many I know already do: ask students at the beginning of a class to inform them privately if they have any issues that might interfere with classroom learning and proceed from there.
After my diagnosis, I felt my own fellowship form. My parents came together to do their best to protect me; they protected me from germs, infections, depression, and loneliness. My best friend and sister provided levity in a dark time much like Merry and Pippin. I met another cancer survivor who proved to be a great guide on my journey, showing me the path to recovery.