
If I were in your shoes....
I'd want to see if I could meet up with this lady and have a chat (a NICE one) there's alot of risk factor here and I'd want to help.. to avoid that risk...rather than shout and get annoyed or righteous which would exacerbate it.
We dont know why... (maybe she's novice, maybe Hubbie has forced dog on her..maybe she herself is scared of it)
But we do know.. she cant fit a muzzle in the first instance and she's struggling.
Do you yourself go to any Dog training clubs in your area..Maybe you could recommend to her to have a chat with the trainers, who in turn may be able to recommend a tried trusted and respected trainer (or 'Bahviouralist') who could one to one with her and her dog????
My sympathies are of course with you, horrid to have a nice walk shattered (next time tho' dont shout.... its petrol on fire!! in this situation ;O) for dog more than owner)
My sympathies are also with this woman tho' you hear of people like this and just wish you could get them to come out for a walk with you, to show them how much better life can be with training the right attitude and the right behaviour.
Sad story...