I'm sorry for the loss of your friend, snood.
I would have to believe that all the intensely calm and positive people I know or know of, who credit their belief in a higher power as the source of their efficacy " to be wrong. I find that impossible to wrap my head around.
Are they necessarily wrong?
They can be totally right that their belief
in a higher power is the source of their calmness, positivity and efficacy... without there being an actual higher power.
I know lots of people who achieve those things without a higher power in the picture.
And then I know lots of other people whose avenue towards that is their belief in a higher power.
As in... if you have a hard time with the belief part, but you want the efficacy et all, I do think there are other ways to get that.
But if you believe, you believe. (And that's totally fine, not something I'd want to talk you or anyone else out of.)