One argument that Christians use against the acceptance of Islam as a faith that worships the true God is that the Koran states that 'Allah is the best of decievers.' We know that God is not a man that he should lie. However, our God does hide Himself, His people and His enemies at times throughout the Bible, as Proverbs 25 v2 tells us, "it is the glory of God to conceal a matter, it is the glory of kings to search a matter out."
Michael Robert Jackson was baptised in the name of Jesus in 2012, after a forty year walk in the wilderness, ten years after he first came to Christ. He is the least of God's children.