The kids club was great working with my six year old son who has high functioning autism and a serious food allergy. But, on the other hand, one of my four year old twins came back with a quite large, fresh abrasion on her nose. When I asked how she got it, she said she and another girl bumped into one another. I asked if the counselors helped her and she said no, that her six year old brother (with autism!) found her crying on the floor and helped her. (I had told them that the "rule" is that they must always help one another when my husband and I aren't there, and his rule driven little self took it to heart, thank goodness.)
I don't know what happened or how long she was upset since neither child is super expressive. He may have seen her two seconds after she fell down. But no counselor ever seemed to notice her bleeding, or if they did they didn't see a need to contact us or mention it at pick up. It's definitely different (in my experience) from our preschool or elementary school where there is a high degree of supervision. (And this was on the Magic).
All that said, my kids (6,4,4) loved kids club and always wanted to go back. I feel comfortable sending them because there are three of them together. But I would be more hesitant with a medically fragile child by himself. Definitely talk to the special needs group. They were very helpful in addressing our concerns before we sailed. And everyone treated the food allergy very seriously. I honestly wish one could arrange a Disney assistant or facilitator even if it were at an additional charge. Even our preschool has provisions for a facilitator if needed. I'm still not a huge fan of the large age range in the club as I think it lends itself to a bit more chaos.