God does indeed heal.
However, the major prophet Daniel, who believed mightily in God and was favored by God was also very learned in science. It has it's place in this world. Nobody ever said that science replaced God. The study of science is how man tries to understand how God spoke this world into existence and clothed the fields with exquisite beauty.
Science, in it's proper context in no way replaces faith in God. It just is a tool to use to help understand why chemicals and other substances do what they do in the human body or else wise.
Children in whom was no blemish, but well favoured, and skilful in all wisdom, and cunning in knowledge, and understanding science, and such as had ability in them to stand in the king's palace, and whom they might teach the learning and the tongue of the Chaldeans.
(
Daniel 1:4)