In either case, should he be held accountable by the Judeo-Christian god for his perspective (and actions or lack of action) since he has been immersed in Islamic culture/environment his entire life?
The answer is YES. He is already condemned.
Romans 9:10
I also find it fascinating that Christians believe some are condemned by God before they are born.
What makes you think it's just "some" who are condemned?
What's amazing, is that God chooses to save some before He created the world.
Yes, we're all condemned from birth, right? Born in sin. I take issue with the idea that the Christian God would condemn a person who was raised in a different faith, truly believed it was right, never was able to see Christianity as true or had no contact with Christianity and thus no opportunity to convert. And the idea that Christians were chosen to be saved by God. Well according to your beliefs yes. But it's still just a matter of where you were born and what you came into contact with during your life, something an individual has little control over. If God has that control, he'd make Christianity so obviously right to everyone there would be no denying it, that would only be just. But maybe I'm overlooking something here.