I love Mrs. Twist because, after watching the movie today, I am convinced she knows about Ennis' and Jack's relationship, and communicates her knowledge, and her sympathies, to Ennis. First there's the comforting hand on his shoulder, the suggestion he go up to the room, the nod in response to the shirts, the paper bag.
Then, as Ennis is going out the door, he nods thanks again for the shirts. They lock eyes -- he actually turns slightly in a very subtle double-take when he sees her expression -- and they hold that look for maybe an extra half a second. In that moment she is telling him she understands, and offering one last wordless gesture of comfort. And he gets it.