I have to admit, I find the image of "shrine" and "relic" as being too far removed from Ennis' earthy nature. Throughout the whole movie he is closed off, yet there are moments when he reveals that he is a tactile person, even when it's just to give a little punch or shove. Which is the reason why the Reunion scene always slays me....from Ennis jittery anticipation, to his ear-grabbing I'm-going-to-swallow-you-whole kiss, to his tender "later" and head nudge, to the way he hooks his thumbs in his pockets because he knows otherwise he will not be able to keep his hand off Jack...Ennis just reveals himself so much.
Every day I see him caressing those shirts, touching the postcard, in an attempt to "stoke" embers of Jack's memory. As if to say, "you're with me today" "I feel you in this moment." Maybe he just leaves that door wide open, so when he catches a glimpse of it out of the corner of his eye, it's like Jack standing there in the front of the closet door. So much more intimate, more personal, than the image I receive when I think of "shrine", "relic","veneration", "benediction".
IMO the blood on Jack's shirt represents BOTH of them, Jack was trying to staunch Ennis' blood with his sleeve and when Ennis slugged him Jack's blood mingled with Ennis'. I can picture Jack looking at that blood mixed together and becoming one - his greatest wish, his steadfast dream. Ennis preserves this, because now he can admit it was his wish, too. My take on it...just thinking out loud.