When a plant is brought in like this, usually there is no making it better- (I have finally learned.)

The orchid books indicate that it is very difficult to differentiate between viruses (untreatable) and fungi (mostly treatable), and some bacteria (some treatable). There are labs to which you can send a leaf to have it tested; however, I have not been able to locate a lab with a reasonable rate. (Reasonable for the "sitter" of others' orchids)

The bottom picture shows the beginning of the development of the splotches on the leaf.