The thing is your boss has made up his mind about you, and I see no way for you to change it except get exceptionally more degraded in your illness, or miracuralously better. Wasting your time and energy on people that repeatedly refuse to understand, or give you respect is futile. I assume that it's because he "knows" people with Lupus that actually makes the situation worse for you because they don't need service dogs, or the same requests you do, then it "must" not be necessary.
First, I'm sorry you're in this situation where you are met with misunderstanding, hostility, and negativity daily. That can't be good for your lupus.
I'm all for educating people, for promoting understanding and tolerance. Being a feminine lesbian, people don't assume I'm gay... I'm also invisible in that community. That means I have to come out all the time, to everyone, to risk rejection, speculation, and even crudeness. Because of my experience I think I have grown into the educator role. I welcome questions, because I feel if people underestand, they can be more accepting. It's also made me hardened. The folks that are just mean or dismissive I cut out of my life or ignore. That means relatives, co-workers, service people that show signs of distaste when "forced" to serve us (cruise steward wouldn't put our beds together, ect). I don't try to educate or tolerate these folks anymore. I bring these coming out experiences into my lupus expeience, and I only bring it up to you, because it probably taints my perspective, but hopefully it helps make it relatable. With lupus, I am also finding myself coming out again and again, because I don't look sick. Were I faced with someone like your boss he would have been cut off from anything except a professional relationship long before. (I'm not suggesting your relationship is un-professional, by any means, but that offices are friendly, and more enjoyable when people can share about their lives.) Because I can be fired for being gay I do not share that with the people at the office until they "find out" or I am comfortable enough with them on a non-professional level. Since your boss feels comfortable enough with you to tell you what he feels you medically "need", then it is not a purely professional relationship, even if it is only one sided on his side. That means if your office is uncomfortable, it's time to address it with your boss, with a witness. If you feel uncomfortable having that conversation, perhaps it's time to go to HR? This also means it's time to keep more of your medical concerns private and your workplace more professional/transactional. (I remember in one post you were trying to help co-workers understand.) that means going in to do your job, keeping to yourself, telling co-workers you'd "rather not discuss it", when they ask questions. It means HR being in your life a whole lot more, and the friendliness of your co-workers a whole lot less. Just keep in mind, HR is always there to protect the company (even if they are nice and act like your friend) not you. Also, it has been my experience in management that HR personnel do not keep things they learn in confidence.
The thing is there must be reasons you continue to go to this same job, and a reason you keep trying with these individuals. So why do you keep trying to help them understand when they keep showing you they don't care enough to do so? Your options, from what you've shared now and in the past, seem to be A) New job, B) Change to transactional/super professional personality at work, C) Continue as you do now and remain frustrated, D) Try harder to get them to understand, causing more issues, and potentially worse Lupus flairs. (Not in any particular ranking.)
Only you can decide what you're willing to put up with and for how long. You are not alone. You can not decide the way others feel or act toward you. You can decide how you feel, and how much you will stick around for or tolerate.
Good luck, and no matter what you do, take care of you first. (Which it sounds like you do, because you took the time to process your feelings about your service dog.) Change is always difficult, like the teething of an infant, but is necessary. Perhaps it is time for a change, which one(s) is up to you.