The thing that annoys me is when people give credit to God for the actions of a human. It's demeaning. I give a beggar money from time to time; they always thank me. That makes me feel happy, that I've done just a little bit to improve someone else's day. If someone said "Thank God" instead of "Thank you", I'd have to bite back the urge to tell them to stop being ungrateful.

I do not take it that way because when I was religious, i fully credited the people who helped me and thanking God did not make me view their help any less. So now that i am no longer religious, it doesn't bother me at all.

One of the frequent results of generosity, no matter how slight, is gratitude. It's not always given voice, but it can be seen in the eyes and the corners of the mouth. Gratitude, however it is expressed, should be accepted and responded to with kindness. This idea will make itself clear if you can place yourself in their shoes. You know you'd be grateful. You know you'd want to express it in some way.

I'm sure he thought of it as a gratitude to you as well, because (in his mind) he was thanking the most important person for delivering someone helpful to him and said he'd pray for you. I think a good response could be, when he said he'd pray for you, to say that you appreciate it but it's not necessary, you're happy to help — and if he really wants to do something to show his gratitude, when he's in a position to do so, he will help out another who's similarly in need.