Suppose there is a man that subscribes to a traditional, Protestant worldview as described by the Apostle's Creed (i.e. Lutherans, Anglicans, Presbyterians, etc).
Suppose this man has an acquaintance that holds non-Christian beliefs (i.e. pagan, new-age, whatever...).
The Christian man also subscribes to relativism, saying that "whatever you believe is right for you," and claims that the non-Christian will go to heaven if he is faithful to his own religion or morals.
Are there any scholars, commentaries or books that address and explore the implications of Christian relativism (e.g. Someone that adheres to both a Christian worldview and a relativistic/postmodern worldview) on individual's salvation?