try going on fb and checking out bruno's story , this might give you some help with this
"Their local vets are strongly advising against a dog cart or a brace and are not willing to explore the option"
"Gotta love the internet"
As a general rule, I'd trust the judgement of a vet who has actually seen the animal than the third (fourth?) hand opinions from over the web.
Are your friends following their vet's guidance in the "self-healing" option? Or are they applying the devices without consulting the on-site vet?