I just had a game in which the HC was in the wheelchair. The coaches in her conference and district have gotten used to it, and they were of no opposition when she requested that her AC would stand and request the timeout when they wanted to request one. We three officials had no problem with it either. Of course, I had no problems with making whatever accomodations because I am a person covered under the ADA as well, and I don't think my partners wanted to mess around on that topic (because they know very well that lecturing about the rights and privileges covered under the ADA is part of my day job!).