SBC
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
And not only so, but also when Rebekah had conceived children by one man, our forefather Isaac, 11though they were not yet born and had done nothing either good or bad--in order that God's purpose of election might continue, not because of works but because of him who calls-- 12 she was told, "The older will serve the younger." 13 As it is written, "Jacob I loved, but Esau I hated." 14 What shall we say then? Is there injustice on God's part? By no means! 15 For he says to Moses, "I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion." 16So then it depends not on human will or exertion, but on God, who has mercy.