So sorry to hear this, JB, and my condolences for the loss of your wife.
While there may be a psychological element to this coming so soon after your sad loss, I would not rule out the viral theory.
Must be about 15 or so years ago, I developed a sore throat, resulting in terrifying croup every night for about about 4 weeks: really thought I'd never be able to draw another breath. My singing voice went out of the window then, very hoarse and unpleasant. It was before the smoking ban, and any attempt to sing in a smoky environment brought on the croup again.
I was referred to an ENT consultant who looked at my vocal cords and send one of them was paralysed, presumed cause being viral. I also had an MRI scan, which ruled out any more serious pathology.
I was reviewed after some months (?^ months), by which time my voice was back to normal and a repeat laryngoscopy showed that both vocal cords were again working properly. So I am throwing out some grains of hope to you, JB for a complete recovery, given time, but that may be measured in months. And one "silver lining" for me was that the "break in register" that plagued me before all this had gone away!
I'll also mention a dear friend, and professional singer, who was unlucky enough to contract adult whooping cough last year (yes, it is on the rise again). she has had to rest her voice completely for months on end,having been used to being able to sing for hours at a time. But she is slowly getting back to it.
And finally, you might find it helpful to go to a speech and language therapist for further advice.
All my best wishes and hopes for safe return of your voice.