Darry probably knows how to sew. Idk I just feel like he would. I don't mean this in a "haha jock likes a girly thing" kinda way, I mean it in a he probably has to fix up a lot of clothes bc his brothers are dummies.
Soda will come back from work and Darry will stop him and be like "your shirt's torn up," and he'll just shrug and keep walking. Or maybe Pony will come back from track or something, and Darry will look at his jeans and go, "you got a rip on your knee." And of course Ponyboy will roll his eyes and groan and pout about how "It's not even a big deal dar! Why do you care about ONE pair of jeans?"
So whenever he has the time or if it annoys him enough, he fixes it. Soda probably doesn't notice because it'll just get ripped in the same spot the next day, but Pony will. And he won't say it, but he's glad his big brother cared about that one pair of jeans.