Dunno how to fix my book; might just declare victory and go home

So I took my two weeks, and I reread THE LONELY YEARS, and it still has one very specific problem I'm not sure how to fix. The problem is that the main antagonists of the piece--the roommates of my protagonist--seem a little underdeveloped and, more than that, not entirely in tune with the problems that my protagonist is dealing with. It's hard to expla…