If you're so afraid of Islam that you will give up on american principles, you've already lost the fight. You have been terrorized. Either religious freedom applies to muslims too or it doesn't apply to anyone.
Well, if youre a Christian, you should already be against Islam-
Quran 5:75 "Christ the son of Mary was no more than a messenger; many were the messengers who passed away before him"
Quran 4:171 "O People of the Scripture, do not commit excess in your religion or say about Allah except the truth. The Messiah, Jesus, the son of Mary, was but a messenger of Allah and His word which He directed to Mary and a soul [created at a command] from Him. So believe in Allah and His messengers. And do not say, "Three"; desist - it is better for you. Indeed, Allah is but one God. Exalted is He above having a son. To Him belongs whatever is in the heavens and whatever is on the earth. And sufficient is Allah as Disposer of affairs."
I can guarantee you Muslims are against Christianity, any Muslim would tell you that you are blaspheming their god.
For being on topic, what are the duties of this man?
I would be unhappy if anyone came to him for guidance. He would not be willing to guide anyone to Jesus.