Sees Jack's old boots, then spots the shirts, hanging in the closet...
His shirt hidden here inside Jack's own shirt,covered with his blood...
From the SS :
"The pair like two skins, one inside the other, two in one. He pressed his face into the fabric and breathed in slowly through his mouth and nose, hoping for the faintest smoke and mountain sage and salty sweet stink of Jack but there was no real scent, only the memory of it, the imagined power of Brokeback Mountain of which nothing was left but what he held in his hands."