What would the Students have done with him? (TFS Spoilers)
Marlon's actions, both after Clementeen found him arguing with Brody in the basement and especially during that faithful hunting trip with her & Tenn's sisters a year or so ago, were notably hard for someone to get absolution through. It has been argued as to whether he could possibly be "redeemed" or what sentence would best be done with him.
However, I believe there's another, more complicated question worth asking: What would each of his peers-the fellow students who he had been surviving with and looking out for for over seven years-have wanted and/or decided to do with him?