. . . But at the same time, he still has muscular issues, tires easily, he has asthma and an immunity disorder. . . besides his facial assemetry issues, you can't tell anything is wrong with him.
And how do I deal with glares and comments from other people without having to contantly explain what is wrong with him?
I have struggled with how to answer your question. I even went and visited your web site to help me figure out how to respond. Part of my understanding of your question came when I realized that Jack is 2 years old. Having a child with a disability is still a rather new concept for you. You have only been adjusting to it for the last 2 1/2 years.
Raising a child with a disability is not easy. Being a child growing up with a disability is not easy. The challenges are a bit different when it is what we call an "invisible" disability (one where someone can not see that the child is disabled just by looking at them). Jack is your baby and you can and should do everything to protect him. But you also must learn how to accept him for who he is, and that includes accepting that the disability is just part of him when you can see it and when you can't. You already know that he is an active, vibrant toddler, who just happens to have issues that bring you to doctor on a regular basis. There are many things he can do, and many limitation to what he is allowed and able to do.
Teaching Jack that he is a little boy who has strengths that will help him live with his disability, is not going to be easy. But it starts with these trips to Disney. You seem to go a lot (I am envious). As he grows up, he will see how you respond to people reacting to his disability and accomodations. The more you are openly accepting of it and the less you try to hide it, the more he will have a positive perception of his own disability.
My mother tried to hide my disability growing up. It took me a long time to learn that it wasn't something to be ashamed of. It wasn't something to hide. Many people are uncomfortable when I talk about my disability (especially in a job interview), but my "invisible" disability dictates how and why I work the way I do. I have learned that people who do not understand and accept this, will not accept me. One key point I learned over the years is that you only tell people as much as they need to know. You also pick terminology that they will quickly understand or accept things. With Jack, you have scoliosis, which most people have at least heard of before, even if they do not know what it is, and you have muscle issues, which if you say he has weak muscles would be more than enough information for most people to understand his needs.
Now there will be times you need or want to tell people more. There will be times you want to say less. Knowing when and to who you have to say what to, will come with time. Will people wonder why you get to keep Jack in a stroller when they do not get to keep their 2 year old in a stroller, YES. Will someone say something, MAYBE. Is this a problem, NO. Will it prevent you from having the best of times at Disney, ONLY IF YOU LET IT. At Jack's age, he probably will not notice. So it is how much you let yourself feel uncomfortable by others lack of knowledge about your son's issues.
Disney is Magical. It is one of the few places on earth where you can take a child with a disability (seen or unseen) and have them be treated like a child first, with all they accomdations they need without being judged by the people running the place. The cast members are wonderful. They will usually bend over backwards to meet the needs of your child. They will do it respectfully, often without the child even knowing it is happening. For example, while at
DisneyLand I let a cast member know the little girl I was with would not be able to stand in line to wait for meeting Minnie Mouse. They said we could go in her house from the back and wait our time on Minnie's couch. When it was her turn, Minnie came over to the couch and visited with her on the couch. That little girl had an "invisible" disability but Minnie Mouse bent over backwards to make her feel special.
I told the cast member the pure minimum of what I needed, and the only reason I told them anything is because the GAC does not tend to work with most Character Meets (or at least they didn't in the past). I do not know what the cast member told Minnie Mouse, but she made the little girl feel very special and gave her extra attention.
Let the Disney Magic happen, and don't worry about what the other guests who do not know your little boy think about the accomodations he needs for a magical Disney visit.
The staffing cuts don't help the situation either. 
