An Orthodox Ivy Leaguer with dreams of marrying his high school sweetheart descends into depression following his best friend’s murder and tries to preserve his relationship, and sanity, while fighting personal demons and hostile classmates.

This is vague – I can’t understand the story.

The most important questions a logline needs to answer are; What specifically must the main character achieve (or fail to achieve) by the end of the story? In other words, what is his goal?? And, what motivates him to achieve said goal? The answers to both allude me after reading this logline.

You describe many different things in the logline; the MC being an “…Orthodox Ivy Leaguer…” (not sure what this means by the way – is there a better description you can use), dreams of marriage, descent into depression, the death of a friend, preservation of relationships and sanity, personal demons, and hostile classmates. None of these seem to logically connect via a cause and effect relationship and a few of the descriptions are simply confusing.

I suggest you identify one major event; either the death of his friend or his girlfriend breaking up with him, and make that the primary motivator for the MC to take action. Then specify one goal, and course of action, that best suits.