yes, Koka, that was what Ennis really wanted from that moment on. Jack by then was in Ennis' heart (shirt). so romantic?
i feel Ennis chose to be by himself because there was no one he could love more than Jack. so, he wouldn't go to his daughter's wedding. and for why Ennis kept, i think so with you that the sweter as a part of his daughter to have with him forever. the daughter whom he loved so much.
if i'm not wrong, Ennis had two babies. there is not much to talk about the other.