1 in 6 is what most people would consider a sizeable minority. You first said none, then said very few, now few. I just think it's strange that you're misleading (whether intentional or not), the very sizeable portion of Israeli Arabs, which is why I'm even bringing this up. Yes, I know that a lot of them are treated like second-class citizens (before this topic strays), so I'm not even really arguing with you.
I just get wary whenever I hear anything related to the mid-east which sounds like propaganda in either direction, and the "Israel is all Jews" misconception is often involved in the anti-Israeli propaganda I've seen (usually by non-Jews, though).
Anyway, on topic, religion is very important to most people. If the doctor can discuss religion in a constructive way with patients, I think it's a great idea. As long as this subject isn't broached in a way that makes the patient uncomfortable, for example if it comes on as a conversion attempt or an otherwise attempt to influence the patient's religious views.