And I do believe that that Jack's love resurfaced during the exchange between Alma Jr. and Ennis at the end of the film. It opened a drawer, so to speak, close to the core of Ennis's heart where Jack's love had always resided. It was not just a sobering moment. It was a moment of awakening, similar to the madeleine incident at the start of Proust's great work. The mere mention of the phrase "He loves me" brought the reality home to Ennis -- that he was loved. And that made all the difference.

Yeah.
The Jr. and dad in trailer scene, to me, is poignant like the last confrontation one, the SNIT, etc. They were powerful turning points for the boys (namely lastly Ennis), however subtle or not..
Jr. answering that question was like an awakening, another powerful lesson but without Jack's coaching. It was very sobering for me to watch Ennis
unable to stifle the emotions being cast out of the window of the trailer perhaps in some dire response to not just Alma Jr. but Ennis' own inexperience of losing something he felt for. He was clearly drawing straws as he spoke to Jr. from the corner of his sun lit face.
Jr. being about the same age now as Ennis had been when Jack had come into his life. Seeing his daughter in 'naive' love must hit Ennis so ironically hard and all at once. Not only does hearing Jr. answer Ennis when he asked ".. He loves you?" touch Ennis, but hearing himself finally ask this question while having never done so for himself when, as he knows now, it had been so damn applicable years back was, I believe, very spiritually stimulating. Ennis and stoic no longer share the same definition.
A little something about how he folds and smells Jr.'s sweater before putting it in his closet above (as opposed to the dead below? Nevermind that eerie idea, just thinking out loud) Jack's protected shirt:
It must have been sobering or maybe just noticable for Ennis to, say, realize he could have worked much better with having been given the lesson of Jr.'s shirt before that of Jack's.
He holds onto Alma Jr.'s shirt, having crossed over to her language of love. But he wouldn't cross that bridge with Jack and, now, putting the sweater up temporarily probably provides grousome contrast between love and its absense; fear itself made Ennis susceptible to learning the hard way.
But now I think he can feel the words come out of his soul when he insists:
If you can't fix it, you got to stand it.