Nicely done Harvey, keeping him warm was most likely the key part in him coming round. I have a glass patio door that the birds often dont see and we get our fair share of accidents. If they're still alive after hitting the window i find that they're almost guaranteed to pull through if you give them an hour or so in a warm, dark place (i use a pet carrier box thing with a towel over the top). I think of it this way, we've intervened with their lives by putting a window somewhere, so we might as well intervene to give them a second chance!
It's great to see that you helped him 

... fine work my friend, it is nice to see the bright eyed little guy survive a dire collision.... and he is quite a handsome bird... great shot.
