Another hopeful sign--it's been 2 yrs since the atrophy. I've known of some dogs with trigeminal nerve tumors and they don't last that long, sad to say. That being said, a friend of mine had a setter that had one-sided atrophy, and it did turn out to be something with the trigeminal nerve, but it was a benign condition. Some sort of nerve damage, but not fatal. Saying a little prayer that your boy's condition is also benign!
And yes, please update as you find the time.
And we'd love to see some pics of your boy if you have some to share with us!