Hi Kristen! 

This is interesting. So when he depresses his jaw he changes the pitch? Looking for some clarity here... like the tone increases/decreases or the severity of his tinnitus changes? 

Have they been to an ENT? How long have they had tinnitus? Any dizziness? Normal cranial nerve screen?

Although dry needling can help with some cases of tinnitus, if the source isn't neuromusculoskeletal in nature, we likely won't be able to impact it. 

You have honestly done a lot of the points that I would have picked to start. Did you get the greater occipital homeostatic point as well? Have you assessed the supra hyoid musculature?