I posted a new thread yesterday about my dog, Kronk's, d-mange and what a dork I apparently have for a vet. I liked him and trusted him every time I've seen him, up until this issue with the mange. My point being, don't trust your vet just because you like him (or her). He may have been very knowledgable and helpful with other issues you've had with your pets, but that doesn't mean he's steering you the right way this time.
I believe Mitaban dips are the most common course of treatment that vets prescribe, so I'm not at all surprised. But that doesn't make it the best treatment. I let my vet do a dip on my boy the day I found out he had d-mange because I didn't know any better. After some research, I learned how toxic the dips were and how dangerous it is to both the animal and the people giving it.
I just went back to the vet yesterday to have some stiches removed and had to have an unpleasant conversation about the dips. He tried to assure me that ... "Mitaban dips are the "only" treatment for demodectic mange. Boosting the immune system is a waste of time because you have to kill the mites. Ivermectin kind of pointless because you have to kill the mites topically (with the dips)". It was obvious I wasn't going to get anywhere with him and will, therefore, be searching for a new vet. At least your vet encouraged you to boost the immune system. Mine wouldn't even do THAT!!!
There are different philosophies of medecine out there, both for pets and for people. Just as I try to avoid harsh chemicals and treatments for myself and my kids, I do the same for my pets. The body has an amazing ability to heal itself if given the proper nutirition, etc. I have been very encouraged by reading all the posts here about people who have been through this. I wish I would have done it two weeks ago when I first found out he had it!