Whereas I generally agree with the comments, I would add one thing. Most everyone seems to be assuming that because Disney provided warnings, this necessarily absolves them from liability. My guess is that there was nothing inherently or unreasonably dangerous about the ride itself, but I am not qualified to make that assessment. There's a possibility that this family or their lawyer has done some pre-suit investigation to determine whether the G-forces or other physical strains on the ride pose an unreasonable risk to riders, even healthy ones. If that is a legitimate issue in this case, then I would not automatically presume that Disney should bear no responsibility here.
In the meantime, I think I read somewhere that if a claim like this is made and the defendant takes steps to reduce the alleged risk in the meantime (like changing the configuration of the ride), that fact isn't admissible in the case. The reasoning is that we don't want companies to not take action that might be in the public interest just because they're afraid to look guilty for the previous condition.