Note that God would be perfectly happy if the man tithed 10% for the poor, and kept the rest for his own family and people. He would be doing far more than most of us, AND doing more than the Commandments even require in regard to the poor.
No, I don’t know if he is a Christian. But if he’s doing what is right, he will still be blessed by God, believer or not.
But you need to be able to feed your own family, and build a strong surplus, before you can feed someone else.
We’d better get to work.