| Well yes a doctor can write a prescription to a patient that they know and have seen for various re-fills and antibiotics and other drugs. Seldom I am seen with a cold, the doctor merley calls some medicine in for me.
As with re-fills, they even have a specific phone number to call in for those. And this would be people they know well from treatment or people they would know. Now thier medical history and medical records would show a need for this medication. As would the records show these were prescribed.
As for as only refering to one other specialist, this is just the way it is normally done. if you want a heart doctor, a doctor will almost always refer it to a specific doctor. Often this is for professional reasons, because of brands used or because they are friends at a club.
If he was refering them and it was not needed, that is incorrect. But of course it would have to be proved the people he sent did not need to be tested. In marketing, a person needing business would remind others that they could use business, like when the office supply salesman comes by and reminds me that we need this or that in our office.
Just refering people to one specialist is just normal operating percedures.
The only issue I see would be, prescribing medicine if not needed,
and prescribing hearing test if not needed. | 
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