Question about Christianity.

So I am a Christian too but I have a question that has just confused me a lot. If someone is born into another religion (or not born into faith) and has never had the opportunity to learn about it (or have been told it's false and bad so they feel scared not to do it) are they going to hell? Also, my friend is very doubtful that God exists and always asks me how God was created. Is there an argument for this type of situation? Usually he says "How was he created?" And I give him the answer of "He's just always been there, only he knows how long." But I don't really see it as a valid argument. Sorry if there are punctual mistakes and bad grammar, I'm on mobile and trying to type this out quickly.