@derp Basically, the collar does nothing to stop the reactivity initially just by wearing it, but once they react in their typical manner and have their neck cranked around by the front of their face, they learn pretty quick barring any kind of permanent injury! Also, it's double the fun because it's an older dog!
A gentle leader is going to do absolutely nothing to address the issues this person is having with their dog, other than being a band-aid solution while they're out on a walk.
When dogs are as reactive as this one apparently is, and, "gone after so many family members", it's time for a legitimate trainer, not ordering something off amazon.
So, they can say fuck it all they want. Doesn't change the fact that they are doing absolutely nothing to address the behaviour beyond medication and a head harness.
Please, if your dog is highly reactive, do the right thing and hire a
legitimate dog trainer to help you out before something bad happens and your dog ends up paying the price for your lack of proper action.