My dog is not getting better- is euthanasia an option?

No, I dont wanna put my dog down, but he is simply not seeing any improvement. Its almost been a month since he is sick, he was officially diagnosed with tick disease. But now I see he has poor coordination, conjunctivitis and doesnt wanna eat anymore. Plus he is so thin and malnourished despite eating well.

There’s a week left for his treatment, but more symptoms have appeared and his health is declining. I've heard bad things about Ehrlichia (if its even that, i might change vet eventually), thats why I seem so grim about him improving.

He is on Doxycycline and Prednisone, its day 15 today.