My father is currently in the hospital on life support, the prognosis isn't good. People are kind enough to "keep me in their prayers" or "pray for you at this difficult time". Is this one of those times I should just bite my tongue and say nothing? Or do I respond? If so, what do I say?
This in regards to certain people who keep saying this too me and do know I don't believe in gods
Sorry to hear about your father. :(
In cases like this, I tend to focus on the fact that their intent is positive. While prayer does no good to help, the sentiment itself is one that shows they care. Arguing with them in this context would be in bad taste. Sometimes you just have to pick you battles. I'd suggest thanking them in a way that doesn't cause a rift, but also allows you to avoid compromising your beliefs. "Thanks for thinking about us." or "Thanks, It's good to know you're there for us." Something in that vain should fit the bill.
In your situation I ask them to pray for the doctors, I'm very glad to hear your father is doing well.