Science measures what is, or has been. It’s categorically unable to measure what might be.
If knowing they are receiving prayers alleviates someone’s stress–giving them peace of mind, or a stillness in their heart–that leads to greater comfort, less reactiveness or less stress, that’s a tangible benefit, albeit one felt only by the prayer recipient. It’s not necessarily measurable by our current methods.
This is even more true for people for whom stress can kill or debilitate: people with high blood pressure, people with heart conditions, people prone to adrenal exhaustion, manic people, depressive people, schizophrenics.
Prayer may not directly contribute to a heart mending after surgery, but how do you measure prayer’s contribution to the heart not further breaking?
I’m not sure you can.
How do you quantitatively measure the impact of prayer on a person’s will to live?
Regularly adhered to, both religion and reason can be bedrocks of faith. One gives you more comfort about the here and now. The other gives you more comfort about the hereafter.
Both have their limits.
In and of themselves, which is better is probably a matter of opinion.
Making assertions based on opinions and calling it science is dishonest–and violent–and needs to be called out for what it is: a coping mechanism used to make us feel more comfortable.