I am sitting here watching the movie and it suddenly occurred to me that for some reason wardrobe intentionally made Ennis look pathetic. For one thing his shirts are always too small.
Now, in the beginning that could be understood. He was with his brother and his shirts were probably hand-me-downs from his brother. He was a big boy so his brother's shirts were too small. Got it.
But, after he became a man and stopped growing couldn't he or someone buy him shirts that fit? Even if you buy in a thrift store you can find shirts that fit.