Oh my word, this is such a powerful and emotional ending! Looking on the face of his enemy his is struck by the memories of how they became that, and seeing him dead, struggles to find value in any of them. That alone packs a mighty punch.

Then the bit with his apartment, setting it up with clues, and my first thought was someone had killed his enemy and done this to frame him, so the twist of his friend having come to look for him, after him being gone so long. As he had looked at the face of the man he called enemy, and found the word did not fit, so had that man, in finding him absent. There is a poignant beauty in your ending, the two having come to that same point, his friend searching the river for him, him then supporting his friends child, then the very ending. There is a balance that seems appropriate given the opening. Yet another great ending!