"Live long and prosper" might work, depending upon the person.
We've had variations on this discussion here at A/N before. My opinion is that ESPECIALLY when a hand is feeding you, fight that urge to bite. They've proven their good intentions just by giving you a ride. I would accept a "god bless you" as coming from the right place, even if it is BS. Just pretend you're in a strange land surrounded by strange people with strange ways. I usually respond to the natives that I appreciate the sentiment. It's not original but sounds as if it's true and heartfelt. I would imagine they scratch their head later as they wonder why I didn't mention god in return.
Sure, no need to overthink these things.
This is so funny because I actually always bring up Star Trek in some way or other when people bring "god" unnecessarily into the conversation. I've actually told a christian before that I live by the motto "Live long and prosper" and they said it sounded too self fulfilling. Obviously not a Star Trek fan.
then he said god bless you. I didn't know what to say.
You should have said "I didn't sneeze, but thanks anyways."
How can you beat "Thank you."? (I like "Live long and prosper" ... and "Peace, and long life") ... but not in this context.