I've read a fair few stories that take that moment and run with it, and honestly, most of them feel a bit off. They either make Darry a straight-up monster, which misses the whole point of his character, or they make Ponyboy so forgiving it's unrealistic. The interesting ones are the slow, quiet explorations of the aftermath—the awkward silence at breakfast, Pony flinching when Darry moves too fast, stuff like that.
I remember one story where the author focused on Sodapop's reaction, caught between his two brothers, and that felt more true. The hitting is a symptom, not the disease. The real story is the pressure, the fear, and the stupid, desperate love that drives them all. Too many fics just want the dramatic whump and comfort without earning it.
Darry isn't a villain, he's a twenty-year-old kid who's had the world dumped on his shoulders. The best stories get that, and show how they all stumble towards understanding, with Soda playing peacemaker until they finally talk. The worst ones just want someone to hug Pony and call Darry abusive.