The water parks are not that great for disabled access, IMHO. Lots of steps. And even at BB, where there is a lift, it is tricky. Once we had a major blowup waiting for the HC entrance to the lift, waited a long time, no CM nearby, when we finally got one, he said DS "did not look handicapped". (He is autistic and has Down Syndrome). (CM was pulled later and would be re-trained, we were told). That was a long time ago. Another time they insisted we wait for the closed up gondola, not the open chairs, because of the autism. OK, I can maybe see that, for safety, but was surprised. We left his chair at the bottom (he was also 6 mo. or so post bi-lateral ankle surgery, walking but tired easily). We had to get off the gondola, and a CM had to bring over a WC for him to use on the lines at the top. (usually he would use the family raft ride, or 2 person slides). Then another CM had to come over and take the WC as we boarded the slide. Then, you get off the slide at various locations all over the park, usually no where near where you left the chair.
Now, I understand all of this, as we went to the waterparks every trip when my kids were young, both of them. It is the nature of the beast. I am ok with it, some things just are what they are. We went when Sean was young, Dad could carry him up the hill, or at BB me or Dad could take him on the lift while the rest of us walked up carrying the tubes (in the OLD days, you even had to haul up the huge family raft!!) Once he got older, we would all go at park opening, Dad would take Sean on one family raft ride with us, then bring him to the lazy river. Meanwhile I would hit the slides with the other 3 kids. We would meet for lunch, and after that, I would leave with Sean. Dad would ride the slides all afternoon with the other kids. It worked well, for many years. So there are ways to make the water parks work, but there are compromises.
We no longer go to the waterparks, instead use the slides at the resorts. But I sure loved those water parks! Even did Summit Plummet a couple of times.