My nephew is able to use switches and some levers but these need to be given to him. He is not able to participate without assistance from another person. In school he has a personal care assistant. If Disney can not provide someone and does not allow a family member to help then I feel they are not in compliance with the American disability act.
If the club were a school, then perhaps they'd have to provide an assistant. But they aren't. The ADA requires certain businesses to make accommodations, but there are many things they don't have to do. For example, every restaurant doesn't have to have the menu in Braille, or have a signer for the deaf, but they do have to have a handicapped stall in bathrooms or an exemption for why they can't accommodate.
I think Disney goes way beyond what is required by law, but there are just going to be some things that a person in a wheelchair can't do. The pools are not accessible, for example. There are excursions that are restricted to those who can board a vehicle or vessel, or walk a short distance.
I think you'll have more luck getting permission for an adult to stay with him than you will trying to get a CM dedicated to him. Allowing someone to stay is the type of accommodation the ADA had in mind, not requiring private businesses to hire staff dedicated to the care of one individual.
If you decide that having an adult stay with him would work, get it in writing and have that document with you. The 20-somethings working at the Club and Lab need to know that an exception has been made (if they do grant that).
Nancy