If you are speaking of Doctors and medicine, I have no argument with you there, just like I won’t argue with a person who had cancer or some other ailment, was prayed for, or attended a mass somewhere, and found that his cancer was cured. There are many documented healings from both catholic or protestant sources where God has acted in a sovereign manner where medicine had failed or at least where God has chosen to operate beyond medicine beyond the need of a human conduit(other than the praying minister and/or deacons).
In that post “human instrument” means healers. But I’m not denying that God can heal directly without anyone’s intercession.