The irony of the name
The irony of the city's name, "Empire Falls," is that it literally sounds like they are saying, "the town will fall." It's the name of nearby waterfalls, but it also sounds like what the city really is—a fallen small town empire.
The ironic ex-wife
Janine had a dilemma to solve: She was fat, ugly, and mean. Ironically though, it seems that she only solved those problems by hating her husband. It seems that she did not try to repair her life AND her marriage, but rather, she repaired her life to spite her marriage. This is ironic because she could have lost weight out of love, but instead, she finds herself motivated by her emotional grudges.
Miles, the anti-hero
Miles is an anti-hero because he never leaves the town. Heroes are those who leave their community behind to adventure, and when they win big in the world, they come back to share the spoils with the town. But Miles is the opposite of that. A small town boy all his life, he settled down before adventuring, and then the boredom and tedium of life slowly robbed him of his joy until by the beginning of the novel, Miles's hero journey is just to get himself out of the hell he created by never living life to the fullest.
The ironic mother
Miles mother did some scandalous stuff back in her day, and Miles never really talked about it with anyone. But, he should have worked through it with Janine, because Miles's understanding of family life was shaped by his mother's indiscretions. So, by hiding his emotional difficulties instead of facing them, he literally repeats them. Miles mother rejected his father, and now Tick's mother is rejecting her father, Miles himself. By running from betrayal, he ends up betrayed and isolated.
David, the other brother
David was an alcoholic for a long time, but after he discovered marijuana, he gave up the booze and grows weed instead. Now he works for the Grill. The irony is simply that David is both a stoner and a crazy good chef. As a foil for Miles, he shows that the stress and anxiety that Miles carries around with him—it's optional. David's relaxed, chilled out demeanor leads him to be highly successful (ironically, because weed is typically viewed as a drug that makes people incredibly lazy).
