Canine Encephalitis, Lyme infection?

My friend's dog Armando was recently diagnosed with Autoimmune Encephalitis. He's gone blind very suddenly and is in a lot of pain. They're going to treat this with steroids, which I suspect will make him feel better. We're hoping he'll get his sight back but the doc says it's 50/50. Of course, it occurred to me it might be a Lyme infection. The vet says it's a common misconception that encephalitis in dogs is caused by Lyme. That seemed really implausible to me, but again I'm not a vet, or a dog owner, and I have zero experience with this. Any thoughts? Thanks!

Without testing for each with very sensitive tests - I'm not sure there's a way to know - and maybe not even then.

Any vet would have a LOT of trouble convincing me to give my dog steroids when they are exhibiting Lyme symptoms though. I have one dog that has had Lyme 3 times, and while I did agree to put him on steroids to help with inflammation from an old injury from when he was a puppy, years before he was infected - I knew he had healed from Lyme first.

What a shame. There could have been so many thing that could have been going on that would have indicated that steroids were not the best choice. I had a dog that was thin, and yet developed Diabetes and went blind in less than a month - steroids would have killed her very quickly as it would have elevated the glucose in her bloodstream significantly.

And, had the dog had any kind of infection, it would be detrimental to give steroids in that case as well.

Again, such a shame. I'm very sorry for your friend's loss.