Just watched episode 2 of the THINFS tour memory videos, and this woman, Mary Jo Duprey, came up with the title "Vocal coach". I found this on Facebook:

https://www.facebook.com/maryjodupreyvocals/

There's even a picture with Jon, and he obviously has mentioned her personally in his RRHOF induction speech, which I must have missed, but so be it...

That should put every discussion to whether or not he (still) has a vocal coach to rest