Tinnitus is a toughie. I got it around 20 years ago or so - came on with a bang. I hated it and finally just got used to it. It comes and goes- never gone, but better or worse according to my energy level. If I am very exhausted, overdo, or get sick, it gets much worse.
It is often caused by hearing high decibel sound; people who use or practice firearms without ear protection often get it, or using any equipment that is makes high decibel noise.
Chinese traditional medicine and my experience is that it can be related to depleted energy, as mine goes up and down. DH recently got it too - he has used heavy equipment, been around machinery and all kinds of loud things for years, his whole life really. He is very careful about ear protection (now!) but maybe not always.
He also finds that when he feels sick or low energy, the tiniitus is worse.
Sadly, I do not know of anything that cures or fixed is, but I have seen references to some herbs that may help, remind me if I don’t post about it, today I won’t be on FR much at all.
One Ayurvedic health practice is to apply oil (any kind of mild vegetable oil - usually refined sesame is recommended, but other oils like coconut or almond are fine) in the ears and also nostrils, for general protection.
Thanks so much - she has been a firearms instructor, but I think she wore ear protection and the problem existed before then. Recently battled extreme fatigue. So it could have been connected to the fatigue.