You said that you speak about God whenever the subject comes about. Sounds like you don't broach the subject of God that often. It is one thing to be a friend to sinners, in that we are seeking to win them to Christ. It is another thing to enter into a friendship that requires us to compromise our faith in Jesus. You must decide where your friendship with this person fits.
Lets continue with the questions.
This is the danger zone. Therefore whoever wishes to be a friend of the world makes himself an enemy of God. We are specifically warned in the Scriptures not to enter into fellowship pacts or alliances with nonbelievers. This does not mean you cannot be a friend to this person. One of the accusations made against Jesus was that He was a friend of sinners.