A person travelled the world caring for the needy, standing with the accused, adopting the orphan, feeding the hungry, befriending the outcast.
Was this person a Christian?
If you are inclined to say, “Well, unless the person tells me what he believes, I can’t say”, then I think you may want to introspect; for beliefs entail action. There is then no distinction to make between calling the person above a Secular Humanist or a Christian if both would do the same things. Both literally believe the same thing.
If there is some other confession inside Christianity that makes some kind of distinction, then it isn’t one that impacts behavior. And like James suggests with faith, what is any “belief” if no action is or can be taken as a result of it? A nice thought perhaps? Quite definitely inconsequential in any practical sense, and perversely moribund if such “nice thoughts” are said to be the centrality of Christianity; a triune God, the Eucharist, proper theology and orthodoxy, etc..
If the person above is as God intended a person to be all along, how is that person not also the logos of God literally? How is that person not the alethea of God, the expressed truth of human nature? How is this person not the zoe of God, and the hodos, the manner and mode humanity is to be in the world; the “way, truth, and life”? How does God not abide in this person while this person abides in God, by participating in the good that God is, and not merely doing the good?
Is it that he must confess something other than what his life already does?