Or maybe ask why he's being so hostile to a possible remedy, so you can better understand his reasoning.
There may be a logical reason for his reaction, or he may be feeling slighted.
It's important that he understands your need to find something which may assist in Tenini's treatment, and you could explain that you feel you've been turned away with little real understanding of the diagnosis and options available.
If you still don't like what his answer is, then consider seeking an alternative veterinary opinion.