Good posts as always Bookcat.
pablope. I would affirm to your friend that a natural faith exists (a natural virtue).
But I would ALSO emphasize that there is a Supernatural faith (a Supernatural virtue).
There are supernatural virtues (sometimes called the “Theological Virtues”) that come with Baptism. These are graces or undeserved “helps” from God through the Sacrament that help unite us to Christ (the unity is itself a grace too).
My point is, supernatural faith IS a grace.
As Pope Benedict stated (in one of Bookcat’s citations) . . . .
Faith is looking at Christ, entrusting oneself to Christ, being united to Christ, conformed to Christ, to his life.
This is not all encompassing on faith (Pope Benedict has said other things too), but I think it gives you a good discussion foundation with your friend.