Okay, then, since lantz isn't quite getting the point, I'm going to link what the Fate/Stay Night LP has documented for Last Episode:
http://lparchive.org/Fatestay-night/Update%20397/Reading it somewhat carefully, there's no real indication here that Shirou ever became a HS. Or even got in there for any sort of heroism. If anything, if I'm reading this right, a lot of it had to do with the fact that Saber wished reeeeeeaaaaaalllly hard for Shirou to be there with her, and after several long journeys on his part,
bam, Avalon. There's not really anything substantive here in terms of world building so much. It's mostly "here's your happy end, Seiba fans!"
Possibly I'm reading some of the Shirou journeying bits wrong, in terms of him doing heroic things. But I can confirm that there's nothing about Shirou becoming a Heroic Spirit or Heroic Spirits being able to enter Avalon in here.