Will Falconer, DVM Moderator
Robyn, you are indeed on an awful hamster wheel with this dog, and nothing is looking bright, no light at the end of the tunnel, until you at least stop vaccinating him. I hear the fear is keeping you getting them, so I'd suggest you review a couple of key pages about Efficacy and Safety of vaccines. I think you'll find the fear slip away and you'll know you can stop vaccinating this poor boy.
If you really want to address this deeply and go for cure, it's time to hire a qualified homeopathic vet. I tell you how to find one, near or far matters not a lick, starting from my Resources page where you'll find the AVH list. This video walks you through how to choose one. This will take time now that he's got such a long history of suppressive drugs and repeated vaccines, but it's the best approach I know of. NOTHING in conventional medicine can cure this guy, that should be pretty obvious by now. All the best to you.