However, he should place his trust in Hashem only. This seems similar to the attitude towards any human endeavour, for a livelihood, etc. Effort is expended, but one must realize that success comes only from Hashem. However, he should not feel that his efforts have brought him success, but rather that his success comes solely from Hashem. This is true in matters of health and sickness as well.
Healing goes under the ruling of saving one's life.
This is true even if another doctor is available, since an ill person does not always merit to be healed through just any doctor. These words of the Shulchan Oruch are taken from the writings of the Ramban in Toras Ho'odom. Please note that the points mentioned in the Sh. O. are from the vantage point of the doctor, not the ill person. It is incumbent upon a person who is truly reliant upon Hashem to place his full trust in Hashem for complete recovery from a health disorder.