This guy does sound like he's got some potential! I know I sound like a broken record sometimes, but he could do worse than learn about Fatima. Then there was St. Francis who walked right up to the Sultan and preached the Faith. St. Vincent de Paul is another great inspiration for Islamic converts. He did manage to convert one while still a slave!
It is tough because unlike Judaism, where you at least have something in common as far as the old testament is concerned, the Koran and Hadith(s) are completely counterfeit and irredeemable. On the other hand, you can make a clean break from it. It can be easier than trying to purge a faulty understanding of sacred texts.
I kind of look at Muslims as having a harder exterior shell to crack, but once they agree to actually allow Christianity some proper consideration without the inclination towards violent rejection, they are more likely to convert. Jєωs would be on the opposite side of the spectrum because culturally they're conditioned to accept and even depend on having many things in common with Christianity on the outside, but at their core lies an almost impenetrable sense of ethnic identity. However, once converted, gold is gold whether it be from flax or stone.