When on a religious trip to Israel, his cardiologist placed a written prayer in the Western Wall during one of the scariest periods for my father.
I'm glad the cardiologist has developed a way to manage the suffering we all go through in this hard life, but his delusions about some deity reading a piece of paper he stuck in the wall had nothing to do with your father's recovery.
This kind of base anti-theism is counterproductive and ultimately meaningless.
On the contrary, it's counterproductive to be such a horrible human being that you disregard the efforts of the people who saved the life of your father. My calling that out and trying to shame that horrible behaviour is very meaningful. If I'm successful, the world will be improved.