There is no way to distinguish between an absent god, an indifferent / non-interventionist god, and a non-existent god. They all behave the same and have the exact same impact.

But props to your co-worker for at least figuring out that god does bupkis.

As an atheist I don't subscribe to a personal 'Big Daddy' Deity up in the sky somewhere. But they do say that prayer has a soothing (settling) effect on the person praying. I'd be kinda like talking to yourself which I think is OK. Quite meditation would be another way to go I think to settle to unsettled mind.