The fact the family can’t sue. They absolutely can (edit: in my opinion). Disney Lawyers believe they can’t ( edit: in their opinion). But wether or not they can is up to a judge in this case. And not up to Disney.
So saying they can’t is false until there is actual clarity.
Edit: that is my opinion of course
I looked into that at one point, but 15$/month is quite steep just for that ( imo )