Running a study that's unethical
You're assuming the conclusion though -- that it's unethical. The argument here is that he tested it on himself specifically in order not to endanger others -- as that would be unethical.
I'd respectfully disagree it is analagous to the "vaccines cause autism" situation. This is trying to claim a potential beneficial medical procedure, not to sow fear or distrust in a long-standing, proven medical practice. And there's nothing in the article that says he is resisting others attempting to confirm or refute his work.
In the spirit of the scientific method, hopefully other scientists try to reproduce the results then it'll get corroboration, or be shot down.
If the brews contain only safe test viruses, it should ethically be a safe experiment. Test for antibodies before and after ingestion to the innocuous viruses and the mechanism is proven or disproven.
Again, he's doing exactly the same thing that scientist that experimented on himself to test if H. Pylori was responsible for peptic ulcers. If he Darwin-Awards himself, that's very unfortunate, but so long as mild, innocuous test viruses are being used, he's not endangering anyone else (I certainly hope he did this with 'safe' test virus varieties, for his own sake as well as others!).