What happens when an atheist fervently prays for someone?

A FB friend of mine who has one foot in Christianity (the philosophy without all the miracle stuff) and the other foot in agnosticism posted that his father went to bed last night able to see fine out of both eyes.
Woke up this morning and he couldn’t see out of one eye. A blood clot had somehow become compressed against his optic nerve and he’ll never see from that eye again. Man, that’s a bummer.
He said, “I don’t believe praying for the optic nerve to return would be within the bounds of reason, but I sure hope he draws strength from all the positive thoughts I’m sending his way.”
I posted that the advances we’ve made in medicines have been staggering and I’ll continue to hold hope out for that.
Then we got to talking on PM, and he mentioned that his Dad likes prayers.
I briefly ran down my religious history, born again in the 80’s and all, and told him I can sure pray for him. I’m good at it. I told him that he has to tell his dad I will or it won’t do any good.

He said he would, so I did.