Havana Syndrome: U.S. and Canadian diplomats targeted with possible weapon causing brain injury and neurological symptoms

Yes, that was mentioned in the media item I saw. A brain tumour had been suspected, he had scans and nothing was found.
Link to an article about the rugby player, Billy Guyton.

The article says that tau proteins are markers of the damage. In that case, there are ways to test the living brain e.g. this written for Alzheimers

 

Interesting, thanks. I do vaguely remember reading something more recently about how there was now a way in some victims of CTE to see some evidence. Perhaps that was it.